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Journal articles on the topic 'Superlattices'

Author: Grafiati

Published: 4 June 2021

Last updated: 9 June 2025

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1

Nasiri, Milad, and Yan Wang. "Evolution of Phonon Spectral Energy Density in Superlattice Structures." Crystals 15, no. 5 (May 9, 2025): 446. https://doi.org/10.3390/cryst15050446.

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Superlattices are a distinctive class of artificial nanostructures formed by the periodic stacking of two or more materials. The high density of interfaces in these structures often gives rise to exotic physical properties. In the context of thermal transport, it is well established that such interfaces can significantly scatter particle-like phonons while also inducing constructive or destructive interference in wave-like phonons, depending on the relationship between the phonons’ coherence lengths and the superlattice’s period thickness. In this work, we systematically investigate the effect

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2

Fullerton, Eric E., Ivan K. Schuller, and Y. Bruynseraede. "Quantitative X-Ray Diffraction From Superlattices." MRS Bulletin 17, no. 12 (December 1992): 33–38. http://dx.doi.org/10.1557/s0883769400046935.

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The physical properties of superlattices have been the subject of considerable interest because a wide range of phenomena associated with very thin films, interfaces, and coupling effects can be studied. Recent areas of activity in metallic superlattices include antiferromagnetic coupling of ferromagnetic layers across nonmagnetic spacer layers, giant magnetoresistance, magnetic surface anisotropy, low-dimensional superconductivity, and anomalous mechanical properties. All of these phenomena are strongly affected by the chemical and physical properties of the individual layers and by the super

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3

Hansen, Monica, Amber C. Abare, Peter Kozodoy, Thomas M. Katona, Michael D. Craven, Jim S. Speck, Umesh K. Mishra, Larry A. Coldren, and Steven P. DenBaars. "Effect Of AlGaN/GaN Strained Layer Superlattice Period On InGaN MQW Laser Diodes." MRS Internet Journal of Nitride Semiconductor Research 5, S1 (2000): 14–19. http://dx.doi.org/10.1557/s1092578300004026.

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AlGaN/GaN strained layer superlattices have been employed in the cladding layers of InGaN multi-quantum well laser diodes grown by metalorganic chemical vapor deposition (MOCVD). Superlattices have been investigated for strain relief of the cladding layer, as well as an enhanced hole concentration, which is more than ten times the value obtained for bulk AlGaN films. Laser diodes with strained layer superlattices as cladding layers were shown to have superior structural and electrical properties compared to laser diodes with bulk AlGaN cladding layers. As the period of the strained layer super

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4

Weng, Hsu Kai, Akira Nagakubo, Hideyuki Watanabe, and Hirotsugu Ogi. "Lattice thermal conductivity in isotope diamond asymmetric superlattices." Japanese Journal of Applied Physics 61, SG (March 10, 2022): SG1004. http://dx.doi.org/10.35848/1347-4065/ac4304.

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Abstract We study the lattice thermal conductivity of isotope diamond superlattices consisting of 12C and 13C diamond layers at various superlattice periods. It is found that the thermal conductivity of a superlattice is significantly deduced from that of pure diamond because of the reduction of the phonon group velocity near the folded Brillouin zone. The results show that asymmetric superlattices with a different number of layers of 12C and 13C diamonds exhibit higher thermal conductivity than symmetric superlattices even with the same superlattice period, and we find that this can be explai

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5

Antropov, N. О., and Е. А. Kravtsov. "Neutron Reflectometry in Superlattices with Strongly Absorbing Rare-Earth Metals (Gd, Dy)." Поверхность. Рентгеновские, синхротронные и нейтронные исследования, no. 8 (August 1, 2023): 11–15. http://dx.doi.org/10.31857/s1028096023070038.

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Polarized neutron reflectometry was used to study Dy/Gd superlattices with different ratios of Dy and Gd layer thicknesses: 1 : 1, 2 : 1, 3 : 1. It has been experimentally shown that the formation of helical magnetic ordering in Dy layers with a period incommensurate with the period of the superlattice appears as a magnetic superlattice reflection, which is forbidden for structural reasons at a ratio of the thicknesses of the Dy and Gd layers 1 : 1. Otherwise, the formation of helical magnetic ordering has little effect on the shape of the neutron reflectometry curves. Thus, the optimization o

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6

Liu, Yang, Xue Yang, Xiaowei Zhou, Peixian Li, Bo Yang, Zhuang Zhao, Yingru Xiang, and Junchun Bai. "Design and Growth of P-Type AlGaN Graded Composition Superlattice." Micromachines 15, no. 12 (November 26, 2024): 1420. http://dx.doi.org/10.3390/mi15121420.

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A graded composition superlattice structure is proposed by combining simulation with experimentation. The structural factors affecting graded symmetric superlattices and graded asymmetric superlattices and their action modes are simulated and analyzed. A Mg-doped graded symmetric superlattice structure with high Al content, excellent structural quality, good surface morphology and excellent electrical properties was grown by MOCVD equipment. The AlxGa1−xN superlattice with Al composition of 0.7 in the barrier exhibits a hole concentration of approximately 5 × 1015 cm−3 and a resistivity of 66

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7

Yu, Yixuan, Avni Jain, Adrien Guillaussier, Vikas Reddy Voggu, Thomas M. Truskett, Detlef-M. Smilgies, and Brian A. Korgel. "Nanocrystal superlattices that exhibit improved order on heating: an example of inverse melting?" Faraday Discussions 181 (2015): 181–92. http://dx.doi.org/10.1039/c5fd00006h.

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Grazing incidence small angle X-ray scattering (GISAXS) measurements reveal that superlattices of 1.7 nm diameter, gold (Au) nanocrystals capped with octadecanethiol become significantly more ordered when heated to moderate temperatures (50–60 °C). This enhancement in order is reversible and the superlattice returns to its initially disordered structure when cooled back to room temperature. Disorder–order transition temperatures were estimated from the GISAXS data using the Hansen–Verlet criterion. Differential scanning calorimetry (DSC) measurements of the superlattices exhibited exotherms (a

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8

Kabalan, Amal A., and Pritpal Singh. "CdTe/PbTe Superlattice Modeling and Fabrication for Solar Cells Applications." Journal of Nano Research 48 (July 2017): 125–37. http://dx.doi.org/10.4028/www.scientific.net/jnanor.48.125.

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Tuning the bandgap of superlattice structures creates devices with unique optical, electronic and mechanical properties. Designing solar cells with superlattice structures increases the range of light energy absorbed from the solar spectrum in the device. A superlattice is a nanostructure composed of alternating thin layers of two materials. The thickness of the constituent materials alters the optical bandgap of the superlattice. This paper discusses a mathematical model which computes the effective bandgap of a CdTe/PbTe superlattice based on a given thickness of the CdTe and PbTe films. The

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9

Islam, Md Tanvirul, Xinkang Chen, Tedi Kujofsa, and John E. Ayers. "Chirped Superlattices as Adjustable Strain Platforms for Metamorphic Semiconductor Devices." International Journal of High Speed Electronics and Systems 27, no. 01n02 (March 2018): 1840009. http://dx.doi.org/10.1142/s0129156418400098.

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Chirped superlattices are of interest as buffer layers in metamorphic semiconductor device structures, because they can combine the mismatch accommodating properties of compositionally-graded layers with the dislocation filtering properties of superlattices. Important practical aspects of the chirped superlattice as a buffer layer are the surface strain and surface in-plane lattice constant. In this work two basic types of InGaAs/GaAs chirped superlattice buffers have been studied. In design I (composition modulated), the average composition is varied by modulating the composition of one of th

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10

Zhao, Lu, Lijuan Zhang, Houfu Song, Hongda Du, Junqiao Wu, Feiyu Kang, and Bo Sun. "Incoherent phonon transport dominates heat conduction across van der Waals superlattices." Applied Physics Letters 121, no. 2 (July 11, 2022): 022201. http://dx.doi.org/10.1063/5.0096861.

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Heat conduction mechanisms in superlattices could be different across different types of interfaces. Van der Waals superlattices are structures physically assembled through weak van der Waals interactions by design and may host properties beyond the traditional superlattices limited by lattice matching and processing compatibility, offering a different type of interface. In this work, natural van der Waals (SnS)1.17(NbS2)n superlattices are synthesized, and their thermal conductivities are measured by time-domain thermoreflectance as a function of interface density. Our results show that heat

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11

Kim, Jin O., Jan D. Achenbach, Meenam Shinn, and Scott A. Barnett. "Effective Elastic Constants of Superlattice Films Measured by Line-Focus Acoustic Microscopy." Journal of Engineering Materials and Technology 117, no. 4 (October 1, 1995): 395–401. http://dx.doi.org/10.1115/1.2804732.

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The effective elastic constants of single-crystal nitride superlattice films have been determined by calculation and by measurement methods. The calculation method uses formulas to calculate the effective elastic constants of superlattices from the measured elastic constants of the constituent layers. The calculated effective elastic constants are tested by comparing the corresponding surface acoustic wave (SAW) velocities calculated for thin-film/substrate systems with the corresponding SAW velocities measured by line-focus acoustic microscopy (LFAM). The measurement method determines the eff

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12

Sidorkin, Alexander, Lolita Nesterenko, Yaovi Gagou, Pierre Saint-Gregoire, Eugeniy Vorotnikov, and Nadezhda Popravko. "Dielectric Properties and Switching Processes of Barium Titanate–Barium Zirconate Ferroelectric Superlattices." Materials 11, no. 8 (August 14, 2018): 1436. http://dx.doi.org/10.3390/ma11081436.

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This article is devoted to the investigation of the dielectric and repolarization properties of barium zirconate and barium titanate BaZrO3/BaTiO3 superlattices with a period of 13.322 nm on a monocrystal magnesium oxide (MgO) substrate. Synthesized superlattices demonstrated a ferroelectric phase transition at a temperature of approximately 393 °C, which is far higher than the Curie temperature of BaTiO3 thin films and bulk samples. The dielectric permittivity of the superlattice reached more than 104 at maximum. As the electric field frequency increased, the dielectric constant of the studie

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13

Zhang, Wei-Chao, Hao Wu, Wei-Feng Sun, and Zhen-Peng Zhang. "First-Principles Study of n*AlN/n*ScN Superlattices with High Dielectric Capacity for Energy Storage." Nanomaterials 12, no. 12 (June 8, 2022): 1966. http://dx.doi.org/10.3390/nano12121966.

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As a paradigm of exploiting electronic-structure engineering on semiconductor superlattices to develop advanced dielectric film materials with high electrical energy storage, the n*AlN/n*ScN superlattices are systematically investigated by first-principles calculations of structural stability, band structure and dielectric polarizability. Electrical energy storage density is evaluated by dielectric permittivity under a high electric field approaching the uppermost critical value determined by a superlattice band gap, which hinges on the constituent layer thickness and crystallographic orientat

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14

Webb, Matthew, Tao Ma, Allen H. Hunter, Sean McSherry, Jonathan Kaufman, Zihao Deng, William B. Carter, et al. "Geometric defects induced by strain relaxation in thin film oxide superlattices." Journal of Applied Physics 132, no. 18 (November 14, 2022): 185307. http://dx.doi.org/10.1063/5.0120176.

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Functional thin film superlattices with stability in extreme environments can lead to transformative performance in optical and thermal applications such as thermophotovoltaics. In this work, key issues associated with defects that prevent layer-by-layer growth in epitaxial, low-miscibility oxide superlattices are investigated. Layer protrusions, approximately 8 nm wide and 3 nm thick, arise from a strain relaxation mechanism in 8 nm bilayer superlattices of Ba(Zr0.5Hf0.5)O3/MgO and propagate through the subsequent superlattice layers forming an inverted pyramid structure that is spatially pha

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15

Gu, X. Wendy, Xingchen Ye, David M. Koshy, Shraddha Vachhani, Peter Hosemann, and A. Paul Alivisatos. "Tolerance to structural disorder and tunable mechanical behavior in self-assembled superlattices of polymer-grafted nanocrystals." Proceedings of the National Academy of Sciences 114, no. 11 (February 27, 2017): 2836–41. http://dx.doi.org/10.1073/pnas.1618508114.

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Large, freestanding membranes with remarkably high elastic modulus (>10 GPa) have been fabricated through the self-assembly of ligand-stabilized inorganic nanocrystals, even though these nanocrystals are connected only by soft organic ligands (e.g., dodecanethiol or DNA) that are not cross-linked or entangled. Recent developments in the synthesis of polymer-grafted nanocrystals have greatly expanded the library of accessible superlattice architectures, which allows superlattice mechanical behavior to be linked to specific structural features. Here, colloidal self-assembly is used to organiz

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16

Kudasov, Yu B., and Dmitry Andreevich Maslov. "Magnetic Structure of Fe/V Superlattices with Variable Thickness of Iron Layers." Solid State Phenomena 152-153 (April 2009): 209–12. http://dx.doi.org/10.4028/www.scientific.net/ssp.152-153.209.

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The model of magnetic structure of Fe/V superlattices is discussed. An individual iron layer of 2 or 3 ML in thickness is assumed to be a XY system. An interlayer interaction through vanadium spacers leads to the appearing of effective field for each iron layer. The infinite and finite superlattices are investigated. Calculations of magnetic structure of Fe2/V12/Fe3/V12 superlattice show that divergence in estimations of the critical temperature obtained by neutron scattering and MOKE is due to inhomogeneity of magnetic moment distribution in the finite superlattice.

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17

XU, MING, WENXUE YU, GUANGMING LUO, CHUNLING CHAI, TONG ZHAO, FAN CHEN, ZHENHONG MAI, WUYAN LAI, ZHONGHUA WU, and DEWU WANG. "ON THE CHARACTERIZATION OF METALLIC SUPERLATTICE STRUCTURES BY X-RAY DIFFRACTION." Modern Physics Letters B 13, no. 19 (August 20, 1999): 663–69. http://dx.doi.org/10.1142/s021798499900083x.

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To solve the problem on the microstructural characterization of metallic superlattices, taking the NiFe/Cu superlattices as example, we show that the structures of metallic superlattices can be characterized exactly by combining low-angle X-ray diffraction with high-angle X-ray diffraction. First, we determine exactly the total film thickness by a straightforward and precise method based on a modified Bragg law from the subsidiary maxima around the low-angle X-ray diffraction peak. Then, by combining with the simulation of high-angle X-ray diffraction, we obtain the structural parameters such

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18

Staszczak, Grzegorz, Iza Gorczyca, Ewa Grzanka, Julita Smalc-Koziorowska, Grzegorz Targowski, and Tadeusz Suski. "Toward Red Light Emitters Based on InGaN-Containing Short-Period Superlattices with InGaN Buffers." Materials 16, no. 23 (November 27, 2023): 7386. http://dx.doi.org/10.3390/ma16237386.

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In order to shift the light emission of nitride quantum structures towards the red color, the technological problem of low In incorporation in InGaN−based heterostructures has to be solved. To overcome this problem, we consider superlattices grown on InGaN buffers with different In content. Based on the comparison of the calculated ab initio superlattice band gaps with the photoluminescence emission energies obtained from the measurements on the specially designed samples grown by metal-organic vapor phase epitaxy, it is shown that by changing the superlattice parameters and the composition of

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19

W. Tian, J. C. Jiang, X. Q. Pan, C.D. Theis, and D.G. Schlom. "Microstructure of PbTi03/SrTi03 Superlattice Grown by MBE." Microscopy and Microanalysis 4, S2 (July 1998): 576–77. http://dx.doi.org/10.1017/s143192760002300x.

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Ferroelectric superlattices have been actively and intensively studied in recent years for their great scientific and technological interest. Superlattice containing Pb-based ferroelectric layers are important among ferroelectric superlattice systems, however, it is difficult to grow such superlattice due to the high volatility of Pb. Recently, great progress has been made in fabricating superlattice structure of PbZrO3/PbTiO3 by multi-ion-beam sputtering’ and molecular beam epitaxy (MBE). In this paper, we report the microstructural investigations of PbTiO3/SrTiO3 superlattice films, which we

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20

Yonezawa, Yu, Hiroyuki Kinbara, Hiroki Umehara, Hirofumi Kakemoto, Takuya Hoshina, Hiroaki Takeda, and Takaaki Tsurumi. "Fabrication of Dielectric/Conductive Hybrid Artificial Superlattices Using Molecular Beam Epitaxy Method." Key Engineering Materials 421-422 (December 2009): 139–42. http://dx.doi.org/10.4028/www.scientific.net/kem.421-422.139.

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Artificial super-lattices of [(BaTiO3)/(SrTiO3)10]4 (BTO10/STO10) were fabricated on STO(001) substrate by the molecular beam epitaxy method (MBE), and the molecular layers of SrRuO3(SRO) was introduced into these superlattices as conductive layers. The superlattices introduced two conductive layers showed the enormous dielectric permittivity. On the other hand, the permittivity of the superlattice introduced one conductive layer was almost same as that of BTO10/STO10. In the case of introducing two conductive layers, the moving electrons between two layers induced the interfacial polarization

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21

Sankin, Vladimir Ilich, Alexey G. Petrov, Pavel P. Shkrebiy, Olga P. Kazarova, and Alexander A. Lebedev. "SiC Natural and Artificial Superlattices for the Implementation of the Bloch Oscillation Process: A Comparative Analysis." Materials Science Forum 1004 (July 2020): 256–64. http://dx.doi.org/10.4028/www.scientific.net/msf.1004.256.

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Bloch oscillations in semiconductors have been studied for several decades. Oscillations were observed in artificial superlattices based on AlGaAs-GaAs proposed Esaki and Tsu, and the natural superlattice based on superstructures SiC. In this paper we considers some base properties of the SiC natural superlattices that are the ground for the Bloch oscillations existence in these materials and attract attention to the some main disadvantages of the artificial superlattices. The experimental detection of the Bloch oscillation-dependent physical effects in semiconductors has been an actual proble

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22

Twigg, M. E., B. R. Bennett, J. R. Waterman, J. L. Davis, B. V. Shanabrook, and R. J. Wagner. "Interfacial properties of GaSb/InAs superlattices." Proceedings, annual meeting, Electron Microscopy Society of America 51 (August 1, 1993): 826–27. http://dx.doi.org/10.1017/s0424820100149969.

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Recently, the GaSb/InAs superlattice system has received renewed attention. The interest stems from a model demonstrating that short period Ga1-xInxSb/InAs superlattices will have both a band gap less than 100 meV and high optical absorption coefficients, principal requirements for infrared detector applications. Because this superlattice system contains two species of cations and anions, it is possible to prepare either InSb-like or GaAs-like interfaces. As such, the system presents a unique opportunity to examine interfacial properties.We used molecular beam epitaxy (MBE) to prepare an exten

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23

Eymery, J. "Localized destructive interference in X-ray specular reflectivity." Journal of Applied Crystallography 32, no. 5 (October 1, 1999): 859–63. http://dx.doi.org/10.1107/s0021889899006238.

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Localized destructive interference can be obtained for specific values of the angle of incidence when studying semiconductor superlattices with X-ray reflectivity at fixed wavelength. Kinematical calculations show that the difference between the real parts of the refractive index of the layers must be small, and that the number of superlattice periods must be optimized to enhance the destructive interference. An experimental example, involving a CdTe/CdZnTe superlattice, and optical matrix simulations for SiGe/Si superlattices are presented to illustrate this effect. Finally, it is shown that

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24

Ren, Shang-Fen, and Jason Stanfield. "Interface Phonon Modes in Strained Semiconductor Superlattices." International Journal of Modern Physics B 12, no. 29n31 (December 20, 1998): 3137–40. http://dx.doi.org/10.1142/s0217979298002222.

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Phonon modes in strained ZnTe/CdSe superlattices are studied. The macroscopic interface modes and two different types of microscopic interface modes are identified. Interface phonon modes in (ZnTe)8(CdSe)8 superlattice with interchange of atomic layers across interfaces are calculated and compared with the results of superlattice with ideal interfaces.

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Hoglund, Eric R., De-Liang Bao, Andrew O’Hara, Sara Makarem, Zachary T. Piontkowski, Joseph R. Matson, Ajay K. Yadav, et al. "Emergent interface vibrational structure of oxide superlattices." Nature 601, no. 7894 (January 26, 2022): 556–61. http://dx.doi.org/10.1038/s41586-021-04238-z.

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AbstractAs the length scales of materials decrease, the heterogeneities associated with interfaces become almost as important as the surrounding materials. This has led to extensive studies of emergent electronic and magnetic interface properties in superlattices1–9. However, the interfacial vibrations that affect the phonon-mediated properties, such as thermal conductivity10,11, are measured using macroscopic techniques that lack spatial resolution. Although it is accepted that intrinsic phonons change near boundaries12,13, the physical mechanisms and length scales through which interfacial e

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Wang, Bruce, Antonio Bianconi, Ian D. R. Mackinnon, and Jose A. Alarco. "Superlattice Delineated Fermi Surface Nesting and Electron-Phonon Coupling in CaC6." Crystals 14, no. 6 (May 24, 2024): 499. http://dx.doi.org/10.3390/cryst14060499.

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The superconductivity of CaC6 as a function of pressure and Ca isotopic composition was revisited using DFT calculations on a 2c–double hexagonal superlattice. The introduction of superlattices was motivated by previous synchrotron absorption and Raman spectroscopy results on other superconductors that showed evidence of superlattice vibrations at low (THz) frequencies. For CaC6, superlattices have previously been invoked to explain the ARPES data. A superlattice along the hexagonal c-axis direction is also illustrative of atomic orbital symmetry and periodicity, including bonding and antibond

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27

Sanina, Viktoriya, Boris Khannanov, and Evgenii Golovenchits. "Optical Control of Superlattices States Formed Due to Electronic Phase Separation in Multiferroic Eu0.8Ce0.2Mn2O5." Nanomaterials 11, no. 7 (June 24, 2021): 1664. http://dx.doi.org/10.3390/nano11071664.

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The effect of optical pumping and magnetic field on properties of the electronic phase separation regions, which are the multiferroic semiconductor heterostructures in the form of superlattices, have been studied in Eu0.8Ce0.2Mn2O5. These superlattices are formed due to self-organization in a dielectric crystal matrix as a result of the competing internal interactions balance and occupy a small crystal volume. The dynamical equilibrium states of superlattices are initially formed during cycling of as-grown samples in a magnetic field. The superlattices in such states are ferromagnetic and elec

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WILSON, K. S. JOSEPH, and K. NAVANEETHAKRISHNAN. "PHONON POLARITON MODES IN QUANTUM DOT SUPERLATTICES." Modern Physics Letters B 18, no. 02n03 (February 10, 2004): 105–12. http://dx.doi.org/10.1142/s021798490400672x.

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The phonon polariton modes in a quantum dot superlattice system are calculated, extending an earlier theory developed for quantum well and quantum well wire superlattices.14 Results are presented for the GaAs/GaP superlattice system as an example. Our findings exihibit the bulk polariton and the quantum well behaviors as limiting cases.

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Jaszczak, J. A., and D. Wolf. "On the elastic behavior of composition-modulated superlattices." Journal of Materials Research 6, no. 6 (June 1991): 1207–18. http://dx.doi.org/10.1557/jmr.1991.1207.

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Atomistic computer simulations are used to systematically investigate the role of interfacial disorder on the elastic behavior of composition-modulated superlattices of fcc metals, represented by simple Lennard–Jones potentials. The structures, energies, and average elastic properties of four types of superlattices with various degrees of interfacial disorder are computed as a function of the modulation wavelength along [001]. The four superlattice types studied include perfectly coherent, incoherent, and two types derived from these by introducing relative twists about [001] between alternati

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Saito, Yuta, Paul Fons, Kirill V. Mitrofanov, Kotaro Makino, Junji Tominaga, John Robertson, and Alexander V. Kolobov. "Chalcogenide van der Waals superlattices: a case example of interfacial phase-change memory." Pure and Applied Chemistry 91, no. 11 (November 26, 2019): 1777–86. http://dx.doi.org/10.1515/pac-2019-0105.

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Abstract 2D van der Waals chalcogenides such as topological insulators and transition-metal dichalcogenides and their heterostructures are now at the forefront of semiconductor research. In this paper, we discuss the fundamental features and advantages of van der Waals bonded superlattices over conventional superlattices made of 3D materials and describe in more detail one practical example, namely, interfacial phase change memory based on GeTe–Sb2Te3 superlattice structures.

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John, J. D., S. Nishimoto, N. Kadowaki, I. Saito, K. Okano, S. Okano, D. R. T. Zahn, et al. "Quantum device designing (QDD) for future semiconductor engineering." Review of Scientific Instruments 93, no. 3 (March 1, 2022): 034703. http://dx.doi.org/10.1063/5.0081544.

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In semiconductor device history, a trend is observed where narrowing and increasing the number of material layers improve device functionality, with diodes, transistors, thyristors, and superlattices following this trend. While superlattices promise unique functionality, they are not widely adopted due to a technology barrier, requiring advanced fabrication, such as molecular beam epitaxy and lattice-matched materials. Here, a method to design quantum devices using amorphous materials and physical vapor deposition is presented. It is shown that the multiplication gain M depends on the number o

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Harfenist, S. A., Z. L. Wang, R. L. Whetten, I. Vezmar, M. M. Alvarez, and B. E. Salisbury. "Three-Dimensional Hexagonal Close-Packed Superlattices of Passivated Ag Nanocrystals." Microscopy and Microanalysis 3, S2 (August 1997): 431–32. http://dx.doi.org/10.1017/s1431927600009041.

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Silver nanocrystals passivated by dodecanethiol self-assembled monolayers were produced using an aerosol technique described in detail elsewhere [1]. Self-assembling passivated nanocrystal-superlattices (NCS's) involve self-organization into monolayers, thin films, and superlattices of size-selected nanoclusters encapsulated in a protective compact coating [2,3,4,5,6,7]. We report the preparation and structure characterization of three-dimensional (3-D) hexagonal close-packed Ag nanocrystal supercrystals from Ag nanocrystals of ˜4.5 nm in diameters. The crystallography of the superlattice and

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Panomsuwan, Gasidit, Nagahiro Saito, and Osamu Takai. "Structural Properties and Microstructures of SrTiO₃/SrTi_1-xNb_xO₃ Superlattices Grown by Ion Beam Deposition." Materials Science Forum 695 (July 2011): 598–601. http://dx.doi.org/10.4028/www.scientific.net/msf.695.598.

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Superlattice structure of SrTiO3and Nb-doped SrTiO3have been epitaxially grown on atomically flat surface of LaAlO3substrates by ion beam deposition method. Epitaxial superlattices were grown at 800 °C in the presence of partial oxygen pressure under optimizing growth conditions. The Nb-doped SrTiO3layers were varied from 2 to 15 unit cell thickness approximately, while SrTiO3layers are maintained at 15 unit cell thickness with 10 periods. The superlattices with various Nb-doped SrTiO3layer thicknesses were investigated using X-ray diffractometer (XRD) and atomic force microscope (AFM), in ord

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Figarova, Sophia, Huseynagha Huseynov, and Vagif Figarov. "Gain in Thermoelectric Figure of Merit of Al<sub>x</sub>Ga<sub>1-x</sub>As/GaAs Type Superlattices Induced by Strong Impurity Screening." Advanced Materials Research 1180 (August 26, 2024): 37–42. http://dx.doi.org/10.4028/p-2yu1ca.

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In multi-layer structures impurity scattering is effectively reduced by the modulation doping in order to achieve high charge carrier mobility and, as a consequence, better device performance. In this paper, the thermoelectric properties of superlattices when electrons are scattered by strongly screened ionized impurities are discussed. In low-temperature and strong screening circumstances, dependence of the thermopower, power factor, and figure of merit on the superlattice period, miniband width, and screening radius is found. For the specified superlattice parameters and ionized impurity con

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Park, K., L. Salamanca-Riba, and B. T. Jonker. "TEM studies of (ZnSe/FeSe) superlattices." Proceedings, annual meeting, Electron Microscopy Society of America 50, no. 2 (August 1992): 1382–83. http://dx.doi.org/10.1017/s0424820100131541.

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Diluted magnetic semiconductors (DMS) are of considerable interest in the area of heterostructures and superlattices because the lattice parameter, energy gap, and effective mass can be “tuned” in a controlled fashion by varying the composition. This tunability has been exploited in the fabrication of DMS superlattices. Since the superlattices can be grown with a wide range of choices of materials, there is a great variety of possible applications requiring magneto-optical properties. However, the lattice mismatch between the constituent layers in the superlattice and between the superlattice

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Goepfert, I. D., E. F. Schubert, A. Osinsky, and P. E. Norris. "Efficient Acceptor Activation in AlxGa1−xN/GaN Doped Superlattices." MRS Internet Journal of Nitride Semiconductor Research 5, S1 (2000): 329–35. http://dx.doi.org/10.1557/s1092578300004464.

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Mg-doped superlattices consisting of uniformly doped AlxGa1−xN and GaN layers are analyzed by Hall-effect measurements. Acceptor activation energies of 70 meV and 58 meV are obtained for superlattice structures with an Al mole fraction of x = 0.10 and 0.20 in the barrier layers, respectively. These energies are significantly lower than the activation energy measured for Mg-doped GaN thin films. At room temperature, the doped superlattices have free hole concentrations of 2 × 1018 cm−3 and 4 × 1018 cm−3 for x = 0.10 and 0.20, respectively. The increase in hole concentration with Al content of t

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37

Högberg, H., J. Birch, M. Odén, J.-O. Malm, L. Hultman, and U. Jansson. "Growth, structure, and mechanical properties of transition metal carbide superlattices." Journal of Materials Research 16, no. 5 (May 2001): 1301–10. http://dx.doi.org/10.1557/jmr.2001.0182.

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Superlattices of TiC/VC have been deposited on MgO(001) substrates by simultaneous direct current metal magnetron sputtering and C60 evaporation in the temperature range 200–800 °C. Thin superlattices (approximately 1000 Å) deposited at 400 °C exhibited an epitaxial growth with abrupt interfaces while films deposited at 200 °C showed a partial loss of epitaxy. At 800 °C roughening by surface diffusion started to degrade the superlattices and introduced a columnar microstructure. A loss of epitaxy was observed for thicker (>7000 Å) superlattice films deposited at 400 °C. The results suggest

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Yun, Hongseok, and Taejong Paik. "Colloidal Self-Assembly of Inorganic Nanocrystals into Superlattice Thin-Films and Multiscale Nanostructures." Nanomaterials 9, no. 9 (September 1, 2019): 1243. http://dx.doi.org/10.3390/nano9091243.

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The self-assembly of colloidal inorganic nanocrystals (NCs) offers tremendous potential for the design of solution-processed multi-functional inorganic thin-films or nanostructures. To date, the self-assembly of various inorganic NCs, such as plasmonic metal, metal oxide, quantum dots, magnetics, and dielectrics, are reported to form single, binary, and even ternary superlattices with long-range orientational and positional order over a large area. In addition, the controlled coupling between NC building blocks in the highly ordered superlattices gives rise to novel collective properties, prov

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Jin, Cai, Wanrong Geng, Linjing Wang, Wenqiao Han, Dongfeng Zheng, Songbai Hu, Mao Ye, et al. "Tuning ferroelectricity and ferromagnetism in BiFeO3/BiMnO3 superlattices." Nanoscale 12, no. 17 (2020): 9810–16. http://dx.doi.org/10.1039/c9nr09670a.

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Superlattice structure provides an effective path for integrating multifunctional properties. The interfacial coupling in the ferromagnetic/ferroelectric superlattices is a possible route to achieve multiferroicity.

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KILLI, MATTHEW, SI WU, and ARUN PARAMEKANTI. "GRAPHENE: KINKS, SUPERLATTICES, LANDAU LEVELS AND MAGNETOTRANSPORT." International Journal of Modern Physics B 26, no. 21 (July 18, 2012): 1242007. http://dx.doi.org/10.1142/s0217979212420076.

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We review recent work on superlattices in monolayer and bilayer graphene. We highlight the role of the quasiparticle chirality in generating new Dirac fermion modes with tunable anisotropic velocities in one dimensional (1D) superlattices in both monolayer and bilayer graphene. We discuss the structure of the Landau levels and magnetotransport in such superlattices over a wide range of perpendicular (orbital) magnetic fields. In monolayer graphene, we show that an orbital magnetic field can reverse the anisotropy of the transport imposed by the superlattice potential, suggesting possible switc

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Toso, Stefano, Dmitry Baranov, Cinzia Giannini, Sergio Marras, and Liberato Manna. "Wide-Angle X-ray Diffraction Evidence of Structural Coherence in CsPbBr3 Nanocrystal Superlattices." ACS Materials Letters 1 (July 16, 2019): 272–76. https://doi.org/10.1021/acsmaterialslett.9b00217.

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Films made of colloidal CsPbBr<sub>3</sub> nanocrystals packed in isolated or densely-packed superlattices display a remarkably high degree of structural coherence. The structural coherence is revealed by the presence of satellite peaks accompanying Bragg reflections in wide-angle X-ray diffraction experiments in parallel-beam reflection geometry. The satellite peaks, also called “superlattice reflections”, arise from the interference of X-rays diffracted by the atomic planes of the orthorhombic perovskite lattice. The interference is due to the precise spatial periodicity of

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Zhu, Zhen Ye, Jing Bai, Fei Lu, and Qian Wang. "First-Principles Study of Polarization Behavior in BaTiO₃/PbTiO₃ Ferroelectric Superlattices." Advanced Materials Research 833 (November 2013): 3–7. http://dx.doi.org/10.4028/www.scientific.net/amr.833.3.

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We performed the first principle calculation to investigate the polarization behavior of BaTiO3(BTO)/PbTiO3(PTO) superlattices with a period-5 superlattice model. The results show that when BTO proportion increases, values of c/a increase and polarizations decrease. In BPT superlattices, polarization in each local layer keeps a constant value, indicating that short-period BPT superlattices can be approximately considered as a single ferroelectric material. Moreover, from analysis of the electrostatic model, we know the directions of internal electric fields in BTO and PTO layers are opposite.

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Sakai, Yuki, and Susumu Saito. "Geometries and Electronic Structure of Graphene and Hexagonal BN Superlattices." MRS Proceedings 1407 (2012). http://dx.doi.org/10.1557/opl.2012.455.

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ABSTRACTRelative stabilities and electronic structure of graphene/h-BN superlattices are discussed in the framework of the density functional theory. Most importantly, relative stabilities between commensurate and incommensurate superlattices are studied. Commensurate graphene/h-BN monolayer superlattices are found to be definitely more stable than incommensurate superlattices. In graphene/h-BN bilayer superlattices, commensurate superlattices are found to be slightly more stable than incommensurate superlattices. Results also imply that a finite pressure can induce transition from an incommen

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Zhang, Enrui, Jinshan Yao, Zhiming Geng, Yueying Hou, Jiayu Dai, and Hong Lu. "Carrier Relaxation Times in InAs/AlAs Superlattices: Modulating by Layers, Temperature, and Carrier Concentrations." Chinese Physics Letters, January 24, 2025. https://doi.org/10.1088/0256-307x/42/2/028501.

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Abstract The InAs/AlAs superlattice structures hold significant potential for application in low-noise avalanche photodetectors. With their performance in practical applications linked to their fundamental physical property of carrier relaxation time, this paper investigates the carrier relaxation times of InAs/AlAs superlattices across various mono-layers, temperatures, and carrier concentrations. Our investigation indicates that relaxation times span several tens of picoseconds, confirming that high-quality interfaces do not significantly reduce relaxation times in the manner that defect sta

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Kumakura, Kazuhide, Toshiki Makimoto, and Naoki Kobayashi. "High Room-Temperature Hole Concentrations above 1019 cm−3 in Mg-Doped InGaN/GaN Superlattices." MRS Proceedings 622 (2000). http://dx.doi.org/10.1557/proc-622-t5.11.1.

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ABSTRACTWe achieved high hole concentrations above 1019 cm−3 at room temperature in Mg-doped InxGa1-xN/GaN (4 nm/4 nm) superlattices grown by metalorganic vapor phase epitaxy. The hole concentrations for the InxGa1-xN/GaN superlattices increased with the In mole fraction, and the maximum hole concentration reached 2.8 Å 1019 cm−3 for the In0.22Ga0.78N/GaN superlattice. The hole concentrations for the superlattices strongly depend on the structural parameters of the superlattices. The band bending due to the strain-induced piezoelectric field and the valence band structures of the InGaN/GaN het

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Rodríguez-González, Rogelio, Heraclio García-Cervantes, Francisco Javier García-Rodríguez, Gerardo Jesús Escalera Santos, and Isaac Rodríguez-Vargas. "Extended states in random dimer gated graphene superlattices." Journal of Physics: Condensed Matter, May 22, 2024. http://dx.doi.org/10.1088/1361-648x/ad4f3c.

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Abstract Ordered and disordered semiconductor superlattices represent structures with completely opposed properties. For instance, ordered superlattices exhibit extended Bloch-like states, while disordered superlattices present localized states. These characteristics lead to higher conductance in ordered superlattices compared to disordered ones. Surprisingly, disordered dimer superlattices, which consist of two types of quantum wells with one type always appearing in pairs, exhibit extended states. The percentage of dissimilar wells does not need to be large to have extended states. Furthermo

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Schuller, Ivan K., Eric E. Fullerton, H. Vanderstraeten, and Y. Bruynseraede. "Quantitative X-Ray Structure Determination of Superlattices and Interfaces." MRS Proceedings 229 (1991). http://dx.doi.org/10.1557/proc-229-41.

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AbstractWe present a general procedure for quantitative structural refinement of superlattice structures. To analyze a wide range of superlattices, we have derived a general kinematical diffraction formula that includes random, continuous and discrete fluctuations from the average structure. By implementing a non-linear fitting algorithm to fit the entire x-ray diffraction profile, refined parameters that describe the average superlattice structure, and deviations from this average are obtained. The structural refinement procedure is applied to a crystalline/crystalline Mo/Ni superlattices and

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Hansen, Monica, Amber C. Abare, Peter Kozodoy, Thomas M. Katona, Michael D. Craven, Jim S. Speck, Umesh K. Mishra, Larry A. Coldren, and Steven P. DenBaars. "Effect of AlGaN/GaN Strained Layer Superlattice Period on InGaN MQW Laser Diodes." MRS Proceedings 595 (1999). http://dx.doi.org/10.1557/proc-595-f99w1.4.

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AbstractAlGaN/GaN strained layer superlattices have been employed in the cladding layers of InGaN multi-quantum well laser diodes grown by metalorganic chemical vapor deposition (MOCVD). Superlattices have been investigated for strain relief of the cladding layer, as well as an enhanced hole concentration, which is more than ten times the value obtained for bulk AlGaN films. Laser diodes with strained layer superlattices as cladding layers were shown to have superior structural and electrical properties compared to laser diodes with bulk AlGaN cladding layers. As the period of the strained lay

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Luo, Chaojie, Guohua Cao, Beilin Wang, Lili Jiang, Hengyi Zhao, Tongrui Li, Xiaolin Tai, et al. "Self-assembly of 1T/1H superlattices in transition metal dichalcogenides." Nature Communications 15, no. 1 (December 4, 2024). https://doi.org/10.1038/s41467-024-54948-x.

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AbstractHeterostructures and superlattices composed of layered transition metal dichalcogenides (TMDs), celebrated for their superior emergent properties over individual components, offer significant promise for the development of multifunctional electronic devices. However, conventional fabrication techniques for these structures depend on layer-by-layer artificial construction and are hindered by their complexity and inefficiency. Herein, we introduce a universal strategy for the automated synthesis of TMD superlattice single crystals through self-assembly, exemplified by the NbSe2-xTex 1T/1

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Schuller, Ivan K. "Magnetic Superlattices." MRS Proceedings 103 (1987). http://dx.doi.org/10.1557/proc-103-335.

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ABSTRACTMagnetic superlattices serve as model systems for the study of thin film, interfacial, proximity, coupling and superlattice phenomena. Due to these phenomena, the physical properties of magnetic superlattices can be tuned in a reproducible fashion by proper control of the preparation process.Magnetic measurements in conjunction with detailed structural characterization provide a fruitful area of research, especially in understanding basic phenomena in magnetism. We describe here briefly a few experimental examples from our work which illustrate the possibilities magnetic superlattices

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