Article
Physics, Condensed Matter
F. Mesquita, G. Copetti, M. A. Tumelero, M. A. Gusmao, C. Radtke, P. Pureur
Summary: Chlorination of single-layer CVD graphene leads to strong hole doping and weak-localization effects due to intrinsic disorder in the as-grown system and chlorination process. The theoretically predicted negative magnetoresistance regime is observed in freshly chlorinated samples. Time-dependent effects in the electrical transport properties of functionalized CVD graphene samples are also observed as adsorbed chlorine is gradually lost.
PHYSICA B-CONDENSED MATTER
(2021)
Article
Nanoscience & Nanotechnology
Alexander K. Fedotov, Uladzislaw E. Gumiennik, Julia A. Fedotova, Janusz Przewoznik, Czeslaw Kapusta
Summary: The study conducted an improved analysis of carrier transport in single-layer graphene and hybrid structures, showing the coexistence of negative and positive contributions in magnetoresistive effect. Various models were used to analyze the dependences on temperature and magnetic field, providing insights into the behavior of electrical resistance in the structures.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2024)
Article
Materials Science, Multidisciplinary
Ke Wang, T. A. Sedrakyan
Summary: Perpendicular magnetic field introduces an anomalous interaction correction to the static conductivity of doped graphene, leading to a proportional relationship between magnetoresistance and inverse temperature. This behavior originates from field-induced breaking of symmetry.
Article
Chemistry, Multidisciplinary
Erick Arguello Cruz, Pedro Ducos, Zhaoli Gao, Alan T. Charlie Johnson, Dario Niebieskikwiat
Summary: In this study, the effect of ferromagnetic nickel nanoparticles on the magnetotransport properties of chemical-vapor-deposited graphene was characterized. It was found that these nanoparticles greatly suppressed the zero-field peak of resistivity caused by weak localization and enhanced the high-field magnetoresistance. The interaction between the graphene and the nickel nanoparticles was attributed to a local exchange coupling, which did not affect the intrinsic transport parameters of graphene, indicating that the changes in magnetotransport properties were purely magnetic in origin.
Article
Nanoscience & Nanotechnology
Robin Singla, Ambika Shankar Shukla, Anil Kottantharayil
Summary: A method to dope monolayer CVD graphene with nitrogen and induce ferromagnetism was demonstrated, showing a coercivity of 222 Oe at low temperatures. Changes in the angle of the applied magnetic field affected the anisotropic magnetoresistance effect in the doped graphene devices, with varying AMR values at different temperatures. The introduction of magnetism in CVD graphene after nitrogen doping was confirmed through magnetic force microscopy and electron spin resonance spectroscopy, suggesting potential applications in spintronics.
Article
Multidisciplinary Sciences
Takuya Iwasaki, Satoshi Moriyama, Nurul Fariha Ahmad, Katsuyoshi Komatsu, Kenji Watanabe, Takashi Taniguchi, Yutaka Wakayama, Abdul Manaf Hashim, Yoshifumi Morita, Shu Nakaharai
Summary: We report on the magnetotransport characteristics of a high-quality graphene device encapsulated in hexagonal boron nitride layers, showing an interplay of quantum interferences in Dirac materials at different temperatures. The elastic scattering mechanism in the hBN/Gr/hBN stacks contrasts with conventional graphene on SiO2, and our ultra-clean graphene device exhibits nonzero magnetoconductance at high temperatures up to 300 K.
SCIENTIFIC REPORTS
(2021)
Article
Materials Science, Multidisciplinary
Qianwen Wang, Tenghua Gao, Takashi Harumoto, Kazuya Ando, Yoshio Nakamura, Ji Shi
Summary: Enhanced linear positive magnetoresistance of graphene is achieved at room temperature by depositing Co particles on the surface, which introduces strong inhomogeneity. The interfacial hybridization between graphene and Co further enhances spatial fluctuation of carrier density and mobility, leading to a higher PMR that is useful for magnetic sensing at room temperature.
Article
Materials Science, Multidisciplinary
Qiuzhen Cheng, Guoyu Xian, Yin Huang, Hui Guo, Lulu Pan, Houbo Zhou, Jing Wang, Senhao Lv, Chengmin Shen, Xiao Lin, Hailong Chen, Yongfeng Li, Haitao Yang, Hong-Jun Gao
Summary: High-quality PtP2 single crystals were successfully prepared by using a tin flux method with optimal molar ratios of Pt and P. For the first time, 3D weak localization effect and negative magnetoresistance (NMR) were observed in these crystals. Defects in PtP2 crystals were found to suppress the NMR effect and magnetic ordered states, providing new platforms for studying different correlated electronic states.
SCIENCE CHINA-MATERIALS
(2023)
Article
Nanoscience & Nanotechnology
Junling Zeng, Wenhao Xie, Heng Zhou, Tong Zhao, Ben Bin Xu, Qinglong Jiang, Hassan Algadi, Zhenyu Zhou, Hongbo Gu
Summary: A nitrogen-doped graphite-like carbon material with controllable carbon microstructures was synthesized from hybrid phthalonitrile resin through high-temperature annealing. By adjusting the annealing temperature, the material exhibited the lowest resistivity of 1.76 Omega center dot cm, a negative magnetoresistance (MR) value of - 6.10% at 9 T, and a negative permittivity over - 10(5) at low frequency. The negative MR effect was attributed to decreased disorder, increased sp(2) and sp(3) hybridized carbon, and enhanced charge carrier mobility with increasing magnetic field. The negative permittivity was explained by the plasma oscillation with delocalized charge carriers and the increased graphitic N in the carbon microstructures. This work provides novel insights for the application of carbonized PN resins in electronic devices.
ADVANCED COMPOSITES AND HYBRID MATERIALS
(2023)
Review
Chemistry, Multidisciplinary
Yuqing Song, Wentao Zou, Qi Lu, Li Lin, Zhongfan Liu
Summary: The fascinating properties of graphene have sparked enormous scientific and industrial interest, but transferring graphene remains a challenge, which can lead to degradation of graphene membrane and surface contamination. For large-scale industrial transfer, cost-effective and environmentally friendly transfer techniques become crucial.
Article
Physics, Applied
Rui Pang, Jianjun Tian, Chaoyang Kang, Longsheng Wang, Haiyang Gu, Mengna Shen, Limin She, Yeheng Song, Xiansheng Liu, Weifeng Zhang
Summary: This paper reports the transport properties of bulk Ta1.04Ru0.78Te4 single crystals. The samples exhibited metallic behavior with a resistivity upturn below approximately 8.6 K, which may be attributed to quantum correction effects. The weakly nonlinear Hall resistivity suggests a p-type and multiband feature, and the magnetoresistance and violation of Kohler's rule further indicate the presence of weak antilocalization in the Ta1.04Ru0.78Te4 single crystal. These findings provide insights into the quantum transport properties of Ta1.04Ru0.78Te4 single crystals for future device design.
APPLIED PHYSICS LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Hongyi Yan, Haiwen Liu
Summary: This study investigates the weak localization and weak antilocalization effects in twisted bilayer graphene on a hexagonal boron nitride substrate. The researchers discovered that interlayer scattering significantly contributes to the conductivity correction, and a double crossover from weak localization to weak antilocalization and back occurs at a specific range of Fermi energy.
Article
Chemistry, Physical
Takuya Iwasaki, Shu Nakamura, Osazuwa G. Agbonlahor, Manoharan Muruganathan, Masashi Akabori, Yoshifumi Morita, Satoshi Moriyama, Shinichi Ogawa, Yutaka Wakayama, Hiroshi Mizuta, Shu Nakaharai
Summary: The study focuses on Anderson localization in Dirac materials and the strong and weak localization phenomena in specific graphene. Negative magnetoresistance was achieved through helium ion irradiation, and for the first time, negative magnetoresistance in graphene devices was observed at room temperature.
Article
Materials Science, Multidisciplinary
Subhadip Jana, T. Senapati, Shwetha G. Bhat, S. N. Sarangi, K. Senapati, D. Samal
Summary: Through quantum interference originated magnetoconductance study, we provide evidence for quenched magnetic impurity scattering in an antiferromagnetic proximity effect. The observation of enhanced effective phase coherence length and the emergence of chiral-anomaly-induced topological response in longitudinal magnetoconductance indicate the suppression of magnetic impurity scattering in the SrCuO2/SrIrO3 bilayer. This work uncovers a practical means to circumvent unintended magnetic impurity scattering and preserve quantum phenomena in complex materials.
Article
Physics, Applied
Shaman Bhattacharyya, Somnath Bhattacharyya
Summary: The text discusses the potential of quantum computers in simulating quantum many-body physics by constructing multiple scattering centers and tunnel barriers to achieve a large return probability for electrons. The combination of tunneling in a double-path circuit results in phase reversal and the generation of the weak anti-localization effect.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Zhengyu Yan, Maria J. G. Guimarey, Khaled Parvez, Chaochao Dun, Oliver Read, Thomas Forrest, Jeffrey J. Urban, Amor Abdelkader, Cinzia Casiraghi, Wajira Mirihanage
Summary: Chemical exfoliation is a cost-effective and simple method for synthesizing graphene. In this work, we demonstrate the use of x-ray pair distribution function to study solution-processed graphene or other 2D materials with atomic resolution, directly in solution. The results confirm the production of single and few-layer graphene, and also reveal a considerable ring distortion caused by the interaction between solvent molecules and graphene nanosheets.
Article
Materials Science, Multidisciplinary
Franziska Martin, Kyujoon Lee, Maurice Schmitt, Anna Liedtke, Aga Shahee, Haakon Thomt Simensen, Tanja Scholz, Tom G. Saunderson, Dongwook Go, Martin Gradhand, Yuriy Mokrousov, Thibaud Denneulin, Andras Kovacs, Bettina Lotsch, Arne Brataas, Mathias Klaeui
Summary: We investigate the current-induced magnetisation manipulation in two-dimensional Fe3GeTe2 material and find that its crystalline structure allows for the presence of both interfacial and bulk spin-orbit torques, enabling efficient magnetisation switching without the need for complex multilayer engineering.
MATERIALS RESEARCH LETTERS
(2023)
Article
Physics, Applied
I. Boventer, H. T. Simensen, B. Brekke, M. Weides, A. Anane, M. Klaeui, A. Brataas, R. Lebrun
Summary: Cavity spintronics is explored by studying the interaction between spintronic and quantum phenomena. Previous studies focused on the hybridization between magnons in ferromagnets and cavity photons. This study demonstrates the realization of antiferromagnetic cavity magnon polaritons. The interaction arises from the collective spin motion in single hematite crystals and the microwave field of integrated cavities. These findings show the potential for harnessing antiferromagnetic cavity magnon polaritons for coherent information exchange.
PHYSICAL REVIEW APPLIED
(2023)
Article
Physics, Multidisciplinary
Yuqing Ge, Jan Rothoerl, Maarten A. Brems, Nico Kerber, Raphael Gruber, Takaaki Dohi, Mathias Klaeui, Peter Virnau
Summary: Efforts to understand skyrmion behaviour often overlook the interaction potentials but these are key to improve predictive modelling. Here, the authors use an Iterative Boltzmann Inversion technique to construct potentials for skyrmion-skyrmion and skyrmion-boundary interactions from a single experimental measurement, finding the two interactions are exponentially repulsive.
COMMUNICATIONS PHYSICS
(2023)
Article
Physics, Applied
Hiroto Masuda, Yuta Yamane, Takeshi Seki, Klaus Raab, Takaaki Dohi, Rajkumar Modak, Ken-ichi Uchida, Jun'ichi Ieda, Mathias Klaui, Koki Takanashi
Summary: We report current-induced magnetization switching in Pt/Co/Ir/Co/Pt multilayers with different Ir layer thicknesses. The domain structures formed during switching vary depending on the magnetization alignment, either ferromagnetic or antiferromagnetic. Numerical calculations reveal the switching dynamics triggered by dual spin-orbit torques for both cases. Our findings deepen the understanding of the switching mechanism in magnetic multilayers and provide a pathway for designing spintronic devices with more efficient spin-orbit torque switching.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
H. Meer, O. Gomonay, A. Wittmann, M. Klaeui
Summary: Antiferromagnetic transition metal oxides are extensively studied in the field of spin-based electronics, commonly used as passive elements in exchange bias-based memory devices. Recent observations of long-distance spin transport, current-induced switching, and THz emission have renewed interest in these insulating materials, which are now considered attractive candidates for active elements in future spintronic devices. This article discusses promising materials systems and recent advances in reading and writing antiferromagnetic ordering, providing an overview of current research and potential future directions in the field of antiferromagnetic insulatronics.
APPLIED PHYSICS LETTERS
(2023)
Article
Multidisciplinary Sciences
Zhizhong Zhang, Kelian Lin, Yue Zhang, Arnaud Bournel, Ke Xia, Mathias Klaeui, Weisheng Zhao
Summary: This study proposes a neural network based on magnon scattering modulated by an omnidirectional mobile hopfion in antiferromagnets. The states of neurons are encoded in the frequency distribution of magnons, and the connections between them are related to the frequency dependence of magnon scattering. By controlling the hopfion's state, hyperparameters in the network can be modulated, realizing the first verified well-functioning meta-learning device. This research not only breaks the connection density bottleneck but also provides a guideline for future designs of neuromorphic devices.
Article
Physics, Applied
G. Masciocchi, M. Fattouhi, E. Spetzler, M. -A Syskaki, R. Lehndorff, E. Martinez, J. McCord, L. Lopez-Diaz, A. Kehlberger, M. Klaeui
Summary: In this work, the authors propose a CMOS-compatible and inexpensive method for applying local strain on a Si/SiOx substrate. They demonstrate how the magnetoelastic energy landscape created by a pair of openings can be used to create pinning sites in a magnetic nanowire, leading to changes in the local magnetic anisotropy. The experimental results are supported by simulations and calculations, and the authors discuss the potential applications of this technology.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Oscar Lee, Robin Msiska, Maarten A. Brems, Mathias Klaeui, Hidekazu Kurebayashi, Karin Everschor-Sitte
Summary: Learning and pattern recognition require memory, which is simulated artificially in conventional CMOS hardware. Dynamical systems naturally provide the necessary memory, complexity, and nonlinearity for unconventional computing approaches. This article focuses on reservoir computing and provides an overview of key physical reservoir works, particularly in the promising platform of magnetic structures, such as skyrmions, for low-power applications. The article also discusses skyrmion-based implementations of Brownian computing, leveraging thermal fluctuations in skyrmion systems, and outlines the important challenges in this field.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Applied
Giovanni Masciocchi, Thomas J. Kools, Pingzhi Li, Adrien A. D. Petrillo, Bert Koopmans, Reinoud Lavrijsen, Andreas Kehlberger, Mathias Klaeui
Summary: In this work, the effects of strain on the perpendicular magnetic anisotropy and magnetization compensation of Co/Gd and Co/Gd/Co/Gd synthetic ferrimagnets are systematically studied. It is found that the presence of in-plane strain increases the perpendicular magnetic anisotropy in the bilayer system. The magnetization compensation of the quadlayer system is not altered by external strain, indicating the resilience of the Co/Gd ferrimagnets against strain. These findings make them suitable candidates for spintronics applications.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Chemistry, Physical
Yael Kapon, Fabian Kammerbauer, Shira Yochelis, Mathias Klaeui, Yossi Paltiel
Summary: Chiral molecules have the potential to create new magnetic devices by locally manipulating the magnetic properties of metallic surfaces. By chemisorbing onto ferromagnets, chiral polypeptides can induce magnetization locally through spin exchange interactions. In this study, magneto-optical Kerr microscopy was used to directly image surface magnetization changes induced by chiral molecules, demonstrating their ability to control and manipulate magnetization.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Physics, Multidisciplinary
Fabian Kammerbauer, Frank Freimuth, Robert Froemter, Yuriy Mokrousov, Mathias Klaeui
Summary: The Dzyaloshinskii-Moriya interaction (DMI) is crucial in the design of advanced spintronic devices, enabling the stabilization of domain walls and topologically non-trivial magnetic textures. This review focuses on the potential to manipulate DMI through electrical fields and currents, offering post-growth control over the sign and strength of DMI. The effects of currents and fields are discussed from both a theoretical and experimental perspective.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2023)
Article
Physics, Applied
Leo Schnitzspan, Mathias Klaeui, Gerhard Jakob
Summary: This study investigates nanosecond superparamagnetic switching in 50-nm-diameter in-plane magnetized magnetic tunnel junctions (MTJs). The circular superparamagnetic tunnel junctions (SMTJs) exhibit probabilistic switching of the magnetic free layer, which can be utilized for random number generation. A low-footprint CMOS circuit is proposed for fast and energy-efficient random-number generation, and the device design can be optimized based on the effects of spin-transfer torque and Joule heating.
PHYSICAL REVIEW APPLIED
(2023)
Article
Materials Science, Multidisciplinary
Tobias Dannegger, Andras Deak, Levente Rozsa, E. Galindez-Ruales, Shubhankar Das, Eunchong Baek, Mathias Klaeui, Laszlo Szunyogh, Ulrich Nowak
Summary: In this study, ab initio calculations were performed to investigate the tensorial exchange interactions of hematite, and a semiclassical Heisenberg spin model was used to understand its magnetic properties. Atomistic spin dynamics simulations were carried out to calculate the equilibrium properties and phase transitions of hematite, particularly the Morin transition. The computed isotropic and Dzyaloshinskii-Moriya interactions were found to agree well with experimental measurements of the Neel temperature and weak ferromagnetic canting angle. Our simulations revealed the delicate balance between dipole-dipole interactions and on-site anisotropies in determining the magnetic phase of the material. Comparison with spin-Hall magnetoresistance measurements on a hematite single crystal showed deviations of the critical behavior at low temperatures, which were attributed to the quantum nature of the fluctuations driving the phase transitions.
Article
Materials Science, Multidisciplinary
Arnab Bose, Fabian Kammerbauer, Rahul Gupta, Dongwook Go, Yuriy Mokrousov, Gerhard Jakob, Mathias Klaeui
Summary: We report and quantify a large orbital-Hall torque generated by Nb and Ru in this study, identified by the strong dependence of the torques on the ferromagnets. We observed a strong enhancement in the dampinglike torques measured in Nb (or Ru)/Ni bilayers compared to Nb (or Ru)/FeCoB bilayers, including a sign reversal in the case of Nb/(Ni or FeCoB) samples. Furthermore, we discovered a significant increase in the measured torques with the increase of ferromagnetic Ni thickness, which may indicate the unique signature of long-range action of the orbital-Hall torques.