Article
Chemistry, Physical
A. Talapatra, J. Arout Chelvane, J. Mohanty
Summary: The research reveals that high ion irradiation doses lead to changes in the magnetic properties of amorphous Tb-Fe-Co films, and the form of magnetic domain modification transitions from rapid domain wall motion to nucleation and propagation of reverse domains.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
Hongyu Chen, Junming Gou, Wentao Jia, Xin Song, Tianyu Ma
Summary: This study investigates the origin of appealing hard magnetic properties in non-equiatomic magnetic high-entropy alloys through detailed microstructural and chemical analysis. The results show that the as-cast alloy has a hierarchically heterogeneous microstructure with nano-arrays enriched or depleted with ferromagnetic element. The aspect ratio and elemental concentration of the nano-arrays can be manipulated by magnetic annealing, significantly enhancing the coercivity.
Article
Materials Science, Multidisciplinary
Xi Chen, Shao-Long Jiang, Dong-Wei Wang, Kang Yang, Jin-Hui Lu, Guang-Hua Yu
Summary: The effect of ultrathin Fe layer on perpendicular magnetic anisotropy (PMA) in Co/Pt multilayers was investigated. The position of the Fe layer at the interface strongly influenced the PMA. When the Fe layer was doped at the Co/Pt interface, the PMA decreased monotonically with increasing Fe layer thickness. However, when the Fe layer was doped at the Pt/Co interface, the PMA showed a peak at a specific thickness. The variation in PMA is mainly attributed to the tuning of electron occupation states at Fe-doped Pt/Co interface.
Article
Physics, Applied
Jiafeng Feng, H. X. Wei, Yong Ren, Xinxi Li, X. F. Han
Summary: This study investigates the magnetoresistance (MR) effect and magnetic properties in (Co/Pt)(4)/Co/IrMn (SFM) and (Co/Pt)(4)/Co/IrMn/(Co/Pt)(2)/Co (DFM) structures. The research finds that the thickness of the IrMn layer has different effects on the antiferromagnetic and MR properties for these two structures. The DFM structure exhibits suppressed antiferromagnetic property and enhanced MR.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Nurcan Yilmaz, Caner Deger, Adem Parabas, Fikret Yildiz
Summary: The study demonstrates that the magnetic properties of (Fe0.5Ni0.5)xRh1_x alloy thin films can be controlled by changing the crystal lattice parameters and composition. Films with a higher concentration of ferromagnetic content exhibit strong in-plane magnetic anisotropy, while perpendicular magnetic anisotropy (PMA) is observed around 40% of FeNi. The main contribution to the PMA around 40% FeNi is found to originate from the tetragonal distortion in the crystal, as shown through first-principles calculations.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Philomela Komninou, Ilias M. Oikonomou, Billy D. Clark, Joseph B. Abugri, Kristin E. Tippey, P. B. Visscher, Subhadra Gupta
Summary: The microstructure of 20 nm thick polycrystalline Co25Pd75 alloy films with perpendicular magnetic anisotropy was studied using TEM techniques. The study examined the influence of different seed layers on the structural quality, crystallite size, compositional homogeneity, and grain boundaries of the Co25Pd75 films. Results showed that Co25Pd75 layers grown on Ta/Pd bilayer and Ta/Ru/Ta trilayer seeds had larger crystalline columns compared to the other samples.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Morito Namba, Hiroshi Takatsu, Riho Mikita, Yao Sijia, Kantaro Murayama, Hao-Bo Li, Ryo Terada, Cedric Tassel, Hiroki Ubukata, Masayuki Ochi, Regino Saez-Puche, Elias Palacios Latasa, Naoki Ishimatsu, Daisuke Shiga, Hiroshi Kumigashira, Katsuki Kinjo, Shunsaku Kitagawa, Kenji Ishida, Takahito Terashima, Koji Fujita, Takeaki Mashiko, Keiichi Yanagisawa, Koji Kimoto, Hiroshi Kageyama
Summary: In this study, an anionic approach was demonstrated to induce intersite charge transfer (ICT) in the oxyhydride perovskite EuVO2H, resulting in increased conductivity and transition temperature (T-C). Furthermore, a large perpendicular magnetic anisotropy was observed in thin films, providing new possibilities for materials with novel functions.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Review
Physics, Applied
Libor Vojacek, Fatima Ibrahim, Ali Hallal, Bernard Dieny, Mairbek Chshiev
Summary: The study proposes an alternative design of magnetic tunnel junctions with greatly enhanced perpendicular magnetic anisotropy based on density-functional-theory calculations, utilizing interfacial perpendicular anisotropy and strain-induced bulk PMA in bcc Co. Fe(3ML)Co(4ML)Fe(3ML) is suggested as a storage layer design for MgO-based STT MRAM cells.
PHYSICAL REVIEW APPLIED
(2021)
Article
Physics, Multidisciplinary
Zhi Li, Kun Zhang, Ao Du, Hongchao Zhang, Weibin Chen, Ning Xu, Runrun Hao, Shishen Yan, Weisheng Zhao, Qunwen Leng
Summary: Thanks to its strong perpendicular magnetic anisotropy, excellent processing compatibility, and novel spintronic phenomenon, Co/Pt multilayers have been widely used in magnetic storage. However, the remanent magnetization (M-r) decreases significantly due to the formation of reversed magnetic domains with increasing layer repetition. To overcome this issue, an ultra-thick granular [Co/Pt](80) multilayer was deposited on a granular SiNx buffer layer, resulting in remarkably improved M-r t value, M-r/M-s ratio, and out of plane coercivity. This work provides a solution for achieving high M (r) t value in ultra-thick Co/Pt multilayers, which is of great potential in high-density magnetic recording applications.
Article
Materials Science, Multidisciplinary
Ji Ho Kang, Sangho Han, Deokyeon Lee, Dong Hun Kim
Summary: The growth behavior and magnetic properties of single-layer Fe thin films sputtered at different temperatures were investigated. The deposition temperature had a significant impact on the surface morphologies and magnetic properties of the films. Co-sputtered Fe-SrTiO3 nanocomposite thin films showed different microstructures and magnetic properties depending on the growth conditions. The modulation of magnetic anisotropy by tuning the geometry and composition of metal-metal-oxide nanocomposites offers a promising approach for the design of future multifunctional devices.
Article
Materials Science, Multidisciplinary
E. V. Skorokhodov, M. V. Sapozhnikov, O. L. Ermolaeva, N. S. Gusev, A. A. Fraerman, V. L. Mironov
Summary: The study investigates ferromagnetic resonance in multilayer thin-film structures using magnetic resonance force microscopy (MRFM), magneto-optical Kerr effect spectroscopy, and magnetic force microscopy. Results show different domain structures at different spatial scales, with specific resonances observed in a labyrinth domain structure. The study demonstrates MRFM's capability to study highly inhomogeneous magnetic states of ferromagnetic structures, especially in zero magnetic fields.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2021)
Article
Chemistry, Physical
Young Chan Won, Jae-Pyoung Ahn, Sang Ho Lim
Summary: This study investigated the perpendicular magnetic anisotropy (PMA) and microstructure of Pt/Co/AlN stacks. It was found that the magnetic moment significantly increased after annealing, leading to strong PMA. The effective PMA energy densities were 2.28 and 1.96 x 10(7) erg/cm(3) after annealing at 300 and 400 degrees C, respectively. High-resolution cross-sectional transmission electron microscopy confirmed the presence of strong PMA.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Physical
E. Yuzuak, G. D. Yuzuak, A. Huetten
Summary: Investigation of the magnetic behavior of nanostructured Tb-Fe-Co thin films reveals that the films composed of fine crystallites around the Fe-Co phase crystallization temperature after heat treatment exhibit unique perpendicular magnetic properties.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Physical
Z. X. Ye, X. T. Zhao, W. Liu, L. Liu, J. X. Wu, Y. Li, J. Ma, H. Z. Ju, Y. H. Song, Z. D. Zhanga
Summary: The influence of Ta spacer layers on the microstructure and magnetic properties of Nd-Dy-Fe-Co-B thick films is systematically studied. Increasing the number and thickness of Ta spacer layers significantly enhances the perpendicular magnetic anisotropy while maintaining a coercivity of around 2 T. The Ta spacer layer facilitates the formation of the out-of-plane texture and enhances the pinning effect, resulting in high coercivity.
SURFACES AND INTERFACES
(2023)
Article
Materials Science, Multidisciplinary
Bo-Yao Wang, Jing-Yu Ning, Tzu-Hsin Li, Chun-Chieh Chung, Chun-Yao Hsu, Ming-Shian Tsai, Tzu-Hung Chuang, Der-Hsin Wei
Summary: This study reports the effects of triggering perpendicular magnetic anisotropy in a ferromagnetic film with strong in-plane magnetic anisotropy through nearby antiferromagnetic films. The results demonstrate that different antiferromagnetic structures can induce perpendicular magnetic anisotropy in the ferromagnetic film through exchange coupling at room temperature or low temperature.
Article
Multidisciplinary Sciences
Fupin Liu, Georgios Velkos, Denis S. Krylov, Lukas Spree, Michal Zalibera, Rajyavardhan Ray, Nataliya A. Samoylova, Chia-Hsiang Chen, Marco Rosenkranz, Sandra Schiemenz, Frank Ziegs, Konstantin Nenkov, Aram Kostanyan, Thomas Greber, Anja U. B. Wolter, Manuel Richter, Bernd Buechner, Stanislav M. Avdoshenko, Alexey A. Popov
NATURE COMMUNICATIONS
(2019)
Article
Chemistry, Physical
Mingu Kang, Linda Ye, Shiang Fang, Jhih-Shih You, Abe Levitan, Minyong Han, Jorge I. Facio, Chris Jozwiak, Aaron Bostwick, Eli Rotenberg, Mun K. Chan, Ross D. McDonald, David Graf, Konstantine Kaznatcheev, Elio Vescovo, David C. Bell, Efthimios Kaxiras, Jeroen Van den Brink, Manuel Richter, Madhav Prasad Ghimire, Joseph G. Checkelsky, Riccardo Comin
Article
Physics, Condensed Matter
Markus Morgenstern, Christian Pauly, Jens Kellner, Marcus Liebmann, Marco Pratzer, Gustav Bihlmayer, Markus Eschbach, Lukacz Plucinski, Sebastian Otto, Bertold Rasche, Michael Ruck, Manuel Richter, Sven Just, Felix Luepke, Bert Voigtlaender
Summary: This article reviews the contributions of surface science methods to the discovery and improvement of 3D topological insulator materials, with examples from the authors’ work. It highlights the significance of spin-polarized angular-resolved photoelectron spectroscopy in demonstrating the spin-helical surface Dirac cone and discovering novel types of topological insulators. Additionally, it introduces procedures for spatially mapping potential fluctuations and identifying topological edge states in weak topological insulators.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2021)
Article
Chemistry, Physical
Kollur Shiva Prasad, Renjith Raveendran Pillai, Madhav Prasad Ghimire, Rajyavardhan Ray, Manuel Richter, Chandan Shivamallu, Anisha S. Jain, Shashanka K. Prasad, P. Sushma, Stevan Armakovic, Sanja J. Armakovic, Raghavendra G. Amachawadi
JOURNAL OF MOLECULAR STRUCTURE
(2020)
Article
Materials Science, Multidisciplinary
D. P. Kozlenko, V. Yu Yushankhai, R. Hayn, M. Richter, N. O. Golosova, S. E. Kichanov, E. Lukin, B. N. Savenko
Summary: The rare-earth Tb metal undergoes a structural phase transition from hcp to Sm-type phase under high pressures, resulting in changes in its magnetic properties. Density functional theory calculations support the experimental findings and provide estimates for volume collapse and transition pressures in real materials.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Physics, Applied
Rajyavardhan Ray, A. K. Himanshu, Golak K. Mandal, Uday Kumar, S. N. Jha, N. Patra, D. Bhattacharya, A. B. Shinde, Manuel Richter, P. S. R. Krishna
Summary: The study resolved the discrepancies over the structural details of Ba(Fe1/2Nb1/2)O-3 ceramics through X-ray diffraction and neutron powder diffraction measurements, revealing a cubic structure. An appropriate value of U for DFT+U calculations was obtained through comparison with X-ray absorption spectroscopy.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Physics, Condensed Matter
Eduardo Carrillo-Aravena, Kati Finzel, Rajyavardhan Ray, Manuel Richter, Tristan Heider, Iulia Cojocariu, Daniel Baranowski, Vitaliy Feyer, Lukasz Plucinski, Markus Gruschwitz, Christoph Tegenkamp, Michael Ruck
Summary: This study discovers a new layered salt Bi12Rh3Cu2I5 with weak 3D topological insulator characteristics, and finds that the presence of copper cations prevents strong coupling between the layers. The results are confirmed through calculations and experiments.
PHYSICA STATUS SOLIDI B-BASIC SOLID STATE PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Rajyavardhan Ray, Banasree Sadhukhan, Manuel Richter, Jorge I. Facio, Jeroen van den Brink
Summary: Even if Weyl semimetals are characterized by quasiparticles with well-defined chirality, the experimental exploitation of this feature is severely limited by pairs of Weyl lattice fermions with opposite chirality, causing the net chirality to vanish. However, this issue can be overcome when both time-reversal and inversion symmetry are broken. By investigating chirality in the carbide family RMC2, we found several members to be Weyl semimetals and demonstrated in NdRhC2, a noncentrosymmetric ferromagnet, that an odd number of Weyl nodes can be stabilized at its Fermi surface by tilting its magnetization. The resulting chiral configuration leads to topological phase transitions and interesting chiral electromagnetic responses, and the tilt direction determines the sign and strength of the net chirality.
NPJ QUANTUM MATERIALS
(2022)
Article
Mathematics, Interdisciplinary Applications
Manuel Richter, Seo-Jin Kim, Klaus Koepernik, Helge Rosner, Arnulf Mobius
Summary: This study compares the numerical accuracy and numerical precision of two electronic structure codes, Wien2k and FPLO, in calculating the total energy. The results show that the total energy data obtained from both codes agree within a difference of less than 10^-6. Wien2k achieves slightly higher accuracy at the cost of larger numerical effort, while FPLO shows higher precision, i.e., less numerical noise in the total energy derivatives, which is useful for evaluating physical properties.
Article
Materials Science, Multidisciplinary
Shiang Fang, Linda Ye, Madhav Prasad Ghimire, Mingu Kang, Junwei Liu, Minyong Han, Liang Fu, Manuel Richter, Jeroen van den Brink, Efthimios Kaxiras, Riccardo Comin, Joseph G. Checkelsky
Summary: In this study, we investigated the electronic structure of the ferromagnetic kagome metal Fe3Sn2 without spin-orbit coupling. We found two energetically split helical nodal lines near K and K' in the Brillouin zone, resulting from the trigonal stacking of the kagome layers. The hopping across A-A stacking introduced energy splitting, while that across A-B stacking controlled the momentum space amplitude of the helical nodal lines. Our findings have important implications for the design of topological materials.
Article
Materials Science, Multidisciplinary
A. Alfonsov, J. Facio, K. Mehlawat, A. G. Moghaddam, R. Ray, A. Zeugner, M. Richter, J. van den Brink, A. Isaeva, B. Buchner, V Kataev
Summary: The recent discovery of magnetic topological insulators has provided new insights into exploring exotic states of matter. By investigating magnetic fluctuations, it has been found that different compounds exhibit contrasting dynamics of Mn spins, with the anisotropy of magnetic fluctuations being controlled by carrier density and potentially impacting electronic topological surface states.
Article
Physics, Multidisciplinary
Madhav Prasad Ghimire, Jorge Facio, Jhih-Shih You, Linda Ye, Joseph G. Checkelsky, Shiang Fang, Efthimios Kaxiras, Manuel Richter, Jeroen van den Brink
PHYSICAL REVIEW RESEARCH
(2019)
Article
Materials Science, Multidisciplinary
Ravi Yadav, Satoshi Nishimoto, Manuel Richter, Jeroen van den Brink, Rajyavardhan Ray
Article
Materials Science, Multidisciplinary
J. Zeisner, A. Alfonsov, S. Selter, S. Aswartham, M. P. Ghimire, M. Richter, J. van den Brink, B. Buechner, V Kataev
Article
Materials Science, Multidisciplinary
Stephan Schonecker, Xiaoqing Li, Manuel Richter, Levente Vitos
