Article
Materials Science, Multidisciplinary
Bipul Kumar Mahato, Anjan Barman
Summary: This study reports the synthesis of stable chains of magnetically aligned zero-valent alpha-Fe nanoparticles and investigates their magnetization reversal mechanism. Experimental measurements and numerical simulations show consistent results for magnetic hysteresis loops with magnetic field applied at various directions, demonstrating that the reversal nucleates from the ends of the chains and progresses through different modes.
JOURNAL OF MATERIALS SCIENCE
(2021)
Article
Materials Science, Multidisciplinary
Pinaki Laha, Bipul Kumar Mahato, Rabindranath Gayen, Subhadeep Datta, Rajdeep Singh Rawat
Summary: This study reports the magnetization reversal mechanism in chain-like structures made of permalloy magnetic nanoparticles. The well-aligned and uniform chains were synthesized using a chemical synthesis method, and it was found that the magnetization reversal is mainly influenced by the spherical vortices and shape anisotropy of the chains.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Xinger Zhao, Zhongqiang Hu, Ting Fang, Yuxin Cheng, Keqing Shi, Yi-Xin Weng, Yongjun Du, Jingen Wu, Mengmeng Guan, Zhiguang Wang, Ziyao Zhou, Ming Liu, Jing-Ye Pan
Summary: The study investigates controlling exchange bias in magnetic multilayers using an electric field, and achieves vector imaging of reversible magnetization reversal through magneto-optical Kerr effect microscopy.
SCIENCE CHINA-MATERIALS
(2022)
Article
Chemistry, Physical
Qizhong Zhao, Fanghua Tian, Tieyan Chang, Kaiyan Cao, Dingchen Wang, Yin Zhang, Chao Zhou, Xiaoqin Ke, Wenliang Zuo, Yu Wang, Sen Yang, Xiaoping Song
Summary: In this study, the magnetization reversal phenomenon in the Ni20Mn3B6 alloy was investigated at low applied fields, revealing two compensation temperatures. The first temperature is attributed to competition between Mn atoms at different positions, while the second arises from moment rotation to satisfy Zeeman energy. This phenomenon enables tunable switching of magnetization between positive and negative values, providing potential applications in spintronic devices and magnetic storage materials.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Chemistry, Physical
Zhu-bai Li, Zhen Zhang, Yuan-zhe Fu, Chao Wang, Lei Wei, Suo Bai
Summary: This work presents a method of preparing composite (Nd,Dy)-Fe-B magnets to enhance coercivity with a slight decrease in remanence. The addition of Dy-Fe-B powders improves the coercivity of sintered magnets. The coexistence of Dy-Fe-B and Nd2Fe14B phases in the magnets leads to an increase in the fluctuation field and a decrease in the domain wall size, resulting in significant improvement in coercivity.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Multidisciplinary
Megumi Suyama, Shinjiro Takano, Tatsuya Tsukuda
Summary: In this study, we investigated the effects of ligands on spontaneous electron transfer between alkanethiolate-protected metal clusters in solution. The rate of electron transfer showed a turnover behavior depending on the total chain length of the ligands. The promotion of electron transfer by longer alkanethiolates was attributed to the elongation of lifetime and the contraction of distance between the clusters due to stronger van der Waals interaction. This alkyl-chain-promoted electron transfer is specific to ultrasmall clusters in solution due to nonuniform ligand layer formation.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Chemistry, Multidisciplinary
Christina Gritsenko, Vladimir Lepalovskij, Mikhail Volochaev, Vladimir Komanicky, Aleksandr Gorkovenko, Hanna Pazniak, Maria Gazda, Nikolai Andreev, Valeria Rodionova
Summary: This study investigates the magnetization reversal processes in NiFe/FeMn exchange biased structures, examining the impact of antiferromagnetic layer thickness and substrate temperature during deposition. Hysteresis loop asymmetry was observed at lower temperatures for samples with antiferromagnetic layer thicknesses greater than 10 nm. The average grain size of FeMn was found to be influenced by both antiferromagnetic layer thickness and substrate temperature variations.
Article
Materials Science, Multidisciplinary
Elias Tanuhadi, Joan Cano, Samar Batool, Alexey Cherevan, Dominik Eder, Annette Rompel
Summary: This study reports the structures of two Ni-12 multicubane compounds, which exhibit different magnetic behaviors compared to conventional Ni-4 cubanes, as determined by magnetic studies and high field and frequency electron paramagnetic resonance (HFEPR). One of the compounds displays the unusual coexistence of slow relaxation of magnetization and a diamagnetic ground state, providing a unique opportunity to study magnetic behavior in excited states. Additionally, both compounds show promising activity as homogeneous HER photocatalysts with efficient charge utilization.
JOURNAL OF MATERIALS CHEMISTRY C
(2022)
Article
Nanoscience & Nanotechnology
Dong Li, Baoshan Cui, Xiaobin Guo, Zhengyu Xiao, Wei Zhang, Xiaoxiong Jia, Jinyu Duan, Xu Liu, Jie Chen, Zhiyong Quan, Guoqiang Yu, Xiaohong Xu
Summary: A current-induced four-state magnetization reversal under zero magnetic field has been achieved in a wedged Ta/MgO/CoFeB/MgO heterostructure with perpendicular magnetic anisotropy. The field-free multi-level reversal is determined by the spin-orbit torque effective field and the current-induced Oersted field, while the formation of intermediate Hall resistance states in multi-state switching depends strongly on current-induced Joule heating. These results provide a pathway for field-free multi-level state reversal, which is significant for developing non-volatile and energy-efficient multi-level memories or artificial neuron devices.
Article
Chemistry, Medicinal
Krys E. A. Batista, Marinalva D. Soares, Marcos G. Quiles, Mauricio J. Piotrowski, Juarez L. F. Da Silva
Summary: The study reveals that changes in the relative stability of transition-metal clusters induced by CO adsorption occur at lower coverages and are mainly influenced by interaction energy and cluster distortion energy. Characterizing all adsorption parameters helps to complement the atomistic understanding of the stability of clusters.
JOURNAL OF CHEMICAL INFORMATION AND MODELING
(2021)
Article
Materials Science, Multidisciplinary
Congxiao Liu
Summary: The magnetization reversal process of exchange biased synthetic antiferromagnet (SAF) at the initial stage back to the exchange biasing direction was analyzed using both static and dynamic methods. The results show that the reversal process can start with either continuous rotation or abrupt switching of magnetization direction, and different layers can have reversal priority depending on their materials parameters.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Physics, Multidisciplinary
Chunli Huang, Nemin Wei, Allan H. MacDonald
Summary: This study explores the quantized anomalous Hall effect in graphene multilayers with flat moire minibands, and suggests a current-driven mechanism for reversing the sign of the Hall effect in these Chern insulators.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
L. Duan, X. C. Wang, J. Zhang, Z. Hu, J. F. Zhao, Y. G. Feng, H. L. Zhang, H. -J. Lin, C. T. Chen, W. Wu, Z. Li, R. Wang, J. F. Zhang, T. Xiang, C. Q. Jin
Summary: We report the synthesis, structure, and magnetism of a compound La3MnAs5 with filled anti-Mn3Si5 type structure. La3MnAs5 crystallizes in a hexagonal structure with face-sharing MnAs6 octahedral chains along the c axis. It exhibits ferromagnetic properties with a Curie temperature of around 112 K. The magnetic critical behavior suggests that La3MnAs5 can be described by a three-dimensional Heisenberg model.
Article
Chemistry, Inorganic & Nuclear
Shivani Sharma, Pavitra N. Shanbhag, Fabio Orlandi, Pascal Manuel, Sean Langridge, Devashibhai Adroja, Milan K. Sanyal, Athinarayanan Sundaresan
Summary: The study revealed the coexistence of C-type and G-type antiferromagnetic ordering in polycrystalline YVO3 at 115K, with the G-type phase growing at the expense of the C-type phase on cooling until it ceases at around 77K. Symmetry analysis showed different origins for the Dzyaloshinskii-Moriya interaction in each phase, possibly explaining the observed magnetization reversal between TN and TS. Additionally, the discussion suggested that magnetic phase separation and weak ferromagnetism may be common mechanisms underlying the magnetization reversal phenomenon in other RVO3 systems.
INORGANIC CHEMISTRY
(2021)
Article
Nanoscience & Nanotechnology
Darya Sandulyak, Anna Sandulyak, Yurij Gorpinenko, Alexander Sandulyak, Maria Polismakova, Igor Solovev
Summary: By using circuit sensor contours made from printed circuit boards and placed between contacting spheres of radius R, magnetic fluxes (micro-fluxes) phi(c) over the cores of spheres with different radii r(c) in a magnetized chain of spheres can be measured, providing information about the magnetic properties of the pipe-layers of a magnetized chain of spheres. The step-by-step changes in magnetic fluxes along the pipe-layers can be judged directly based on the step-by-step data phi(c) obtained from the eight sensors. The obtained phi(p) data along the thin pipe-layers of different relative radii r(p)/R were used to find and characterize the induction values and magnetic permeability of each pipe-layer, which are of fundamental importance for fine magnetic separation.
Article
Chemistry, Multidisciplinary
Sreya Pal, Pratap Kumar Pal, Raisa Fabiha, Supriyo Bandyopadhyay, Anjan Barman
Summary: This research reports a new phenomenon involving the coupling between spin waves and hybridized phonon-plasmon waves in a nanostructured media. The interaction leads to the emergence of acousto-plasmo-spin waves that exhibit a wide frequency range. The study of this phenomenon provides insights into nonlinear coupling, parametric amplification, and frequency comb physics, and suggests the potential for designing novel active metamaterials with enhanced response and frequency mixing capabilities.
ADVANCED FUNCTIONAL MATERIALS
(2023)
Editorial Material
Physics, Applied
B. Flebus, S. M. Rezende, D. Grundler, A. Barman
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Physics, Applied
J. M. Flores-Camacho, Bivas Rana, R. E. Balderas-Navarro, A. Lastras-Martinez, Yoshichika Otani, Jorge Puebla
Summary: We investigated the optical properties of NM/Co20Fe60B20/MgO heterostructures using mid infrared spectroscopic ellipsometry. We obtained the dielectric function of Co20Fe60B20 for the first time and determined the dielectric tensor properties of a 2DEG at the NM and CoFeB interface. The interfacial properties, 2DEG Drude parameters, and SOC strength were found to depend on the type of NM.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2023)
Article
Physics, Condensed Matter
Angshuman Deka, Bivas Rana, YoshiChika Otani, Yasuhiro Fukuma
Summary: In this study, the FMR signals excited by applying a microwave signal across the metal-oxide junction in CoFeB/MgO heterostructures were investigated. The results showed that besides the voltage-controlled in-plane magnetic anisotropy (VC-IMA) torque induced by the electric field, significant contributions also arise from spin-torques and Oersted field torques originating from the flow of microwave current through the metal-oxide junction.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Nanoscience & Nanotechnology
Suchetana Mukhopadhyay, Sudip Majumder, Surya Narayan Panda, Anjan Barman
Summary: In this study, the ultrafast demagnetization in 20 nm thick cobalt, nickel, and permalloy thin films was compared using an all-optical pump-probe technique. The experimental results showed a positive correlation between demagnetization time and damping factor with pump excitation fluence. Reservoir coupling parameters were extracted from numerical simulations to reproduce the experimental data, and the spin flip scattering probability for each system was estimated. The fluence-dependence of the extracted coupling parameters may reflect the role of nonthermal electrons in magnetization dynamics at low laser fluences.
Review
Multidisciplinary Sciences
Chandrima Banerjee, Anjan Barman
Summary: The research in spintronics aims to advance memory and computation technology using the spin degree of electron. The use of femtosecond optical pulses triggers the fastest changes in the magnetic state of matter, leading to high speed and energy efficient opto-spintronic memory. The discovery of all optical switching of magnetization in different materials has improved the fundamental understanding of light-spin interaction on ultrashort timescale and showed promise for technological applications.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES INDIA SECTION A-PHYSICAL SCIENCES
(2023)
Article
Multidisciplinary Sciences
Bivas Rana, YoshiChika Otani
Summary: Magnetic damping in thin films often exhibits anisotropic behavior with magnetization orientation. In this study, we investigated the anisotropy of damping in Ta/CoFeB/MgO heterostructures and found that it contains four-fold and two-fold anisotropy terms. The four-fold anisotropy is attributed to two-magnon scattering, while the two-fold anisotropy is correlated with the in-plane magnetic anisotropy of the films, suggesting its origin in the bulk spin-orbit coupling of the CoFeB film. These findings have implications for the design of future spintronics devices.
SCIENTIFIC REPORTS
(2023)
Article
Physics, Applied
Mateusz Golebiewski, Hanna Reshetniak, Uladzislau Makartsou, Maciej Krawczyk, Arjen van den Berg, Sam Ladak, Anjan Barman
Summary: The research on the properties of spin waves in three-dimensional nanosystems is an innovative idea in the field of magnonics. Understanding the nature of magnetization dynamics and binding of spin waves in various parts of magnetic systems opens up possibilities for their use in magnonic and spintronic devices. This study investigates the effect of geometry and external magnetic field manipulations on the localization and dynamics of spin waves in crescent-shaped waveguides using numerical methods. It is found that changing the magnetic field direction in these waveguides breaks the symmetry and affects the localization and frequency of eigenmodes. Additionally, crescent-shaped structures exhibit significant saturation at certain field orientations, resulting in a cylindrical magnetization distribution. Chirality-based nonreciprocal dispersion relations for high-frequency spin waves controlled by the field direction are proposed.
PHYSICAL REVIEW APPLIED
(2023)
Article
Nanoscience & Nanotechnology
Arundhati Adhikari, Sudip Majumder, YoshiChika Otani, Anjan Barman
Summary: Bicomponent magnonic crystals (BMCs) are metasurfaces formed using two dissimilar materials, which enable a richer manipulation of spin waves for spin-wave based computation and communication. The interplay between Co50Fe50 and Ni80Fe20 in a BMC is studied, and the interface engineered coupling is combined with long-range dipolar coupling. Systematic variation of the filling fraction of Co50Fe50 and Ni80Fe20 in the BMC tunes these couplings, and the spin-wave spectra are highly sensitive to the bias-field strength. Numerical simulations demonstrate long-distance and high-speed spin-wave propagation controlled by the filling fraction and a diode-like on/off mechanism determined by the applied magnetic field strength. These observations contribute to the development of high-speed reconfigurable magnonic devices controlled by external parameters.
ACS APPLIED NANO MATERIALS
(2023)
Article
Quantum Science & Technology
Pratap Kumar Pal, Sudip Majumder, YoshiChika Otani, Anjan Barman
Summary: Hybrid dynamical systems have gained momentum due to their physical properties and engineering standpoint, particularly in information processing. Magnon-magnon coupling is identified in Ni80Fe20 nanocross array with a low number of spins (10^12) and is tunable via external parameters. Simulations reveal both static and dynamical dipolar coupling contribute to the observed anticrossing phenomenon. Mode-softening of spin wave tunable by bias-field orientation changes is also observed. These findings enrich hybrid phenomena with a magnonic platform.
ADVANCED QUANTUM TECHNOLOGIES
(2023)
Article
Materials Science, Multidisciplinary
Soma Dutta, Arindam Samanta, Surya Narayan Panda, Saibal Roy, Anjan Barman
Summary: The ultrafast magnetization dynamics of electrodeposited cobalt phosphorus (CoP) alloy with in-plane magnetic orientation (phi) are investigated, revealing dominant two-fold and moderate four-fold anisotropy in the magnetization precession. The Gilbert damping coefficient also exhibits a four-fold anisotropy as a function of phi. The ultrafast demagnetization, on the other hand, is nearly isotropic with respect to phi. These findings suggest that spin-orbit coupling plays a major role in anisotropic precessional dynamics, but its effect is negligible for ultrafast spin-flip scattering processes. These detailed studies of ultrafast spin dynamics provide important insights for potential applications in high-frequency integrated magnetic passives on-chip.
JOURNAL OF MATERIALS SCIENCE
(2023)
Article
Multidisciplinary Sciences
S. Shekhar, S. Mielcarek, Y. Otani, B. Rana, A. Trzaskowska
Summary: We investigated the frequency-wavevector dispersion of thermally excited surface acoustic waves in CoFeB/MgO heterostructures with varying CoFeB thickness. The experimental results were confirmed by simulations based on finite element method. The extracted elastic parameters of CoFeB layer and the effective elastic parameters of the whole stacks are useful for understanding the interaction of phonons with other quasiparticles.
SCIENTIFIC REPORTS
(2023)
Article
Materials Science, Multidisciplinary
Surya Narayan Panda, Sucheta Mondal, Sudip Majumder, Anjan Barman
Summary: In this study, the effects of femtosecond laser pulses on the magnetization dynamics in Ni80Fe20 thin films were investigated using time-resolved magneto-optical Kerr effect magnetometry. The experimental results show significant changes in the magnetization dynamics, including variations in demagnetization time, remagnetization time, enhancement of the Gilbert damping parameter, and a redshift in the precessional frequency, with increasing excitation energy. It was experimentally verified that spin-flip scattering and intraband electron conductivity contribute to the ultrafast demagnetization and damping processes.
Article
Materials Science, Multidisciplinary
Suchetana Mukhopadhyay, Pratap Kumar Pal, Subhadeep Manna, Chiranjib Mitra, Anjan Barman
Summary: Efficient room-temperature spin pumping is demonstrated in Sub/BiSbTe1.5Se1.5/Co20Fe60B20/SiO2 thin films using all-optical time-resolved magneto-optical Kerr effect magnetometry. The spin-mixing conductances of the interface and the spin diffusion length in the films are determined, indicating their potential as promising materials for spin-orbitronic devices.
NPG ASIA MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Sudip Majumder, J. L. Drobitch, Supriyo Bandyopadhyay, Anjan Barman
Summary: We observed strong tripartite magnon-phonon-magnon coupling in a two-dimensional magnetoelastic crystal, where energy transfer and the formation of a new quasi-particle occurred when the frequencies and wavevectors of the three modes matched. This coupling phenomenon exhibited significant anisotropy.
NPG ASIA MATERIALS
(2023)