Article
Materials Science, Multidisciplinary
Quentin Remy
Summary: We propose an extension to simple s-d models to simulate ultrafast magnetization dynamics and spin transport in metallic heterostructures. We introduce an alternative spin dissipation channel caused by a finite exchange splitting of the s band and identify three different mechanisms governing the dynamics of spin accumulation. Based on our theory, we explain the subpicosecond reversal of a ferromagnet in rare-earth free spin valves and support the conclusion of J. Igarashi et al. favoring magnetization reversal due to the rotation of the spin polarization of a reflected spin current.
Article
Physics, Multidisciplinary
A. A. Sirenko, P. Marsik, L. Bugnon, M. Soulier, C. Bernhard, T. N. Stanislavchuk, Xianghan Xu, S-W Cheong
Summary: Terahertz vortex beams with different superposition of orbital and spin angular momentum were used to study antiferromagnetic resonances in single crystals. Strong vortex beam dichroism for AFM resonances in external magnetic field was observed, showing that the sign of orbital angular momentum dominates over conventional circular polarization.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Applied
B. Hussain, Z. Haghshenasfard, M. G. Cottam
Summary: This paper presents a theoretical analysis of spin waves in single- and double-layered nanorings using a microscopic or Hamiltonian-based formalism. The calculations are applied to different magnetic states, showing that coupled spin waves can be controlled by varying the spacer thickness. Numeric simulations are conducted on permalloy nanorings with realistic dimensions and magnetic parameter values.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Yuying Yang, Mengmeng Wei, Wei Qin
Summary: The study found that photo-magnetic coupling was generated through direct spin-photon interactions in organic ferromagnetic crystals. Spin angular momentum can be directly transferred from the polarized spin of an electron to a photon, altering the polarized state of light. When the temperature exceeds the Curie temperature of organic ferromagnets, spontaneous spin polarization is not generated, leading to the disappearance of photo-magnetic coupling.
APPLIED MATERIALS TODAY
(2021)
Article
Mathematics, Applied
Zi-Hua Weng
Summary: This paper applies octonions to explore the influence of external torque on the angular momentum of fluid elements, uncovering the interconnection with vortex streets. It highlights the importance of understanding the impact of external torque on fluid dynamics and its relationship with angular momentum.
MATHEMATICAL METHODS IN THE APPLIED SCIENCES
(2023)
Article
Chemistry, Multidisciplinary
Haiming Yu, Jilei Chen, Vincent Cros, Paolo Bortolotti, Hanchen Wang, Chenyang Guo, Florian Brandl, Florian Heimbach, Xiufeng Han, Abdelmadjid Anane, Dirk Grundler
Summary: Electromagnetic metasurfaces, created by arranging elements with dimensions below the wavelength, can modulate a material's response to electromagnetic waves. This study reports the use of ferromagnetic metasurfaces to manipulate the transmission of spin waves in thin ferrimagnetic insulators. The efficiency of the metasurface is demonstrated to be 98.5%, with potential applications in on-chip control of microwaves.
ADVANCED FUNCTIONAL MATERIALS
(2022)
Article
Optics
Xiaojin Yin, Ziyue Zhao, Pengqi Hao, Jinhong Li
Summary: The spin-orbit interactions of circularly polarized beams and circularly polarized vortex beams in radial gradient-index (GRIN) fibers are analyzed using the generalized Huygens-Fresnel principle and the GRIN fiber's ABCD matrix. The spin angular momentum (SAM) is only related to the polarization helicity, while the orbital angular momentum (OAM) is only related to the topological charge m. These two quantities do not crosstalk or convert between each other. No spin-orbit interactions occur at the focal plane of the GRIN fiber. The same characteristics are observed for partially coherent circularly polarized beams and partially coherent circularly polarized vortex beams in the GRIN fiber.
Article
Materials Science, Multidisciplinary
Junyeon Kim, Dongwook Go, Hanshen Tsai, Daegeun Jo, Kouta Kondou, Hyun-Woo Lee, YoshiChika Otani
Summary: The research demonstrates efficient torque generation without heavy elements in ferromagnetic metal/Cu/Al2O3 trilayers. The effective spin Hall conductivity in these structures can be one order of magnitude higher than heavy-metal based multilayers, suggesting a direction for magnetic nanodevices based on orbital angular momentum injection.
Article
Materials Science, Multidisciplinary
Motomi Aoki, Ei Shigematsu, Ryo Ohshima, Teruya Shinjo, Masashi Shiraishi, Yuichiro Ando
Summary: In this study, it was found that the Low-frequency ST FMR signal enables high sensitivity detection of magnetization switching, while an additional background signal BG was observed, and the sign of the BG signal changes by changing the nonmagnetic material. Further investigation revealed that the BG signal is induced by spin-dependent unidirectional spin Hall magnetoresistance, which is not related to magnetization dynamics but has broader applicability.
Article
Physics, Applied
Bharat Grover, Binoy Krishna Hazra, Tianping Ma, Banabir Pal, Nirel Bernstein, Amit Rothschild, Abhay Kant Srivastava, Samiran Choudhury, Georg Woltersdorf, Amir Capua, Stuart S. P. Parkin
Summary: In this study, the dependence of the spin Hall angle θSH was investigated in epitaxial Al2O3/Pt, MgO/Pt films using a spin-torque driven ferromagnetic resonance method. It was found that the electrical technique had limitations in accurately quantifying θSH at high current densities and could result in erroneous values, particularly for films with large inhomogeneous broadening. The study also revealed a strong dependence of θSH on the crystallographic direction.
APPLIED PHYSICS LETTERS
(2022)
Article
Physics, Applied
Yaroslav Tserkovnyak, Eran Maniv, James G. Analytis
Summary: Current-induced spin torques in layered magnetic heterostructures have similarities across different magnetic materials, but their consequences depend on the nature of the order and whether there is a net magnetic moment. The presence of a net magnetic moment allows for unipolar switching capability in the system, while magnetically compensated materials tend to evolve into limit cycles with chirality dependent on the torque sign under large torques.
APPLIED PHYSICS LETTERS
(2021)
Article
Nanoscience & Nanotechnology
Kyoul Han, Kyung Jae Lee, Sanghoon Lee, Xinyu Liu, Margaret Dobrowolska, Jacek K. Furdyna
Summary: We investigated current-induced spin-orbit fields (SOFs) in a crystalline (Ga,Mn)As ferromagnetic film with four-fold in-plane anisotropy. By designing a Hall device with current channels along crystallographic 100 directions, we observed the effects of SOFs in all four magnetization transitions. The analysis revealed that the Dresselhaus-type SOF is stronger than the Rashba-type SOF, and the values obtained from different current channels are consistent.
Article
Physics, Applied
Shehrin Sayed, Seokmin Hong, Xiaoxi Huang, Lucas Caretta, Arnoud S. Everhardt, Ramamoorthy Ramesh, Sayeef Salahuddin, Supriyo Datta
Summary: Materials with spin-orbit coupling are of great interest for spintronics applications, but there is currently no unifying physical framework to design material systems and devices with desired properties. By analyzing experimental data in a unified manner, it was found that the density of states in a material plays a crucial role in determining the charge-spin interconversion efficiency, leading to a simple inverse relationship. Furthermore, two figure of merits related to the efficiency of spin-orbit-torque and the inverse Rashba-Edelstein effect length show good agreement with existing experimental data across a wide variety of materials.
PHYSICAL REVIEW APPLIED
(2021)
Article
Physics, Applied
Bushra Hussain, Michael G. Cottam
Summary: A theoretical analysis is conducted for the quantized spin waves in single-layered ferromagnetic nanorings with interfacial Dzyaloshinski-Moriya interactions (DMI). The inclusion of DMI effects shifts the transition field value between vortex and onion states and significantly modifies the spin-wave frequencies, with the largest effects observed near the transition field.
JOURNAL OF APPLIED PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Qingwei Fu, Like Liang, Wenqiang Wang, Liupeng Yang, Kaiyuan Zhou, Zishuang Li, Chunjie Yan, Liyuan Li, Haotian Li, Ronghua Liu
Summary: In this study, we experimentally observed the presence of net spin-orbit torques (SOT) in single conductive ferromagnet metal (HM) bilayers. In addition to the expected in-plane (IP) damping-like SOT, we also observed an unexpected out-of-plane (OOP) damping-like SOT. Using spin-torque ferromagnetic resonance technique, we measured the efficiencies of both IP and OOP SOT in pure Py. We propose that the IP SOT is primarily related to the Py bulk spin Hall effect, while the unconventional SOT is attributed to the out-of-plane polarized spin current generated from the nonequilibrium spin swapping effect. Furthermore, we found that these self-induced SOTs are also present in other commonly studied HM/FM multilayer systems, especially those with low conductivity.