Article
Multidisciplinary Sciences
Lukas Powalla, Jonas Kiemle, Elio J. Koenig, Andreas P. Schnyder, Johannes Knolle, Klaus Kern, Alexander Holleitner, Christoph Kastl, Marko Burghard
Summary: Researchers have discovered local tunable spin polarization in current-driven graphene/WTe2 heterostructures using magneto-optical Kerr microscopy. They have presented a theoretical model explaining the spatial distribution of the Kerr signal and revealed the significant potential of 2D heterostructures for spintronics.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Condensed Matter
M. Beens, K. A. de Mare, R. A. Duine, B. Koopmans
Summary: A 'toy model' is presented to describe the spin-polarized hot electron transport and spin pumping processes. The model is used to compare the contributions of these two processes and it is found that spin pumping dominates the injected spin current.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Chemistry, Multidisciplinary
Yan Li, Dongxing Zheng, Bin Fang, Chen Liu, Chenhui Zhang, Aitian Chen, Yinchang Ma, Ka Shen, Haoliang Liu, Aurelien Manchon, Xixiang Zhang
Summary: This study reports the unconventional spin pumping and magnetic damping phenomena observed in an insulating compensated ferrimagnet Gd3Fe5O12. The divergence of the nonlocal effective magnetic damping induced by spin pumping close to the compensation temperature in GdIG/Cu/Pt heterostructures is identified, and the coherent and incoherent spin currents generated by spin pumping and the spin Seebeck effect undergo a distinct direction change with the variation of temperature. These findings broaden the conventional paradigm of the ferromagnetic spin pumping model and open new opportunities for exploring ferrimagnetic magnonic devices.
ADVANCED MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
F. Macia, M. Mirjolet, J. Fontcuberta
Summary: Spin pumping across interfaces between metallic SrVO3 and ferromagnetic Ni80Fe20 is reported. The data shows an efficient spin pumping process, with a significantly higher spin mixing conductance value compared to metallic Vanadium and isoelectronic VO2. The results can be rationalized in terms of the density of states at the Fermi level and the relative strength of electron-electron correlations and electron-lattice coupling.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Multidisciplinary Sciences
Z. Q. Qiu
Summary: This commentary summarizes recent progress on spin pumping by ferromagnetic resonance in magnetic heterostructures, with a focus on the chirality dependence of the spin current.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
M. Cosset-Cheneau, L. Vila, G. Zahnd, D. Gusakova, V. T. Pham, C. Grezes, X. Waintal, A. Marty, H. Jaffres, J-P Attane
Summary: Experimental evidence of spin absorption orientation dependence in ferromagnetic materials is provided, facilitating the quantification of spin-mixing conductance. The obtained values suggest a limitation by the Sharvin conductance, challenging traditional models based solely on Larmor, transverse decoherence, and spin diffusion lengths.
PHYSICAL REVIEW LETTERS
(2021)
Article
Materials Science, Multidisciplinary
Eirik Holm Fyhn, Jacob Linder
Summary: We theoretically study the effect of a rotating electric field on a diffusive nanowire and find an effect similar to spin pumping, resulting in a measurable spin-voltage along the axis of rotation.
Article
Materials Science, Multidisciplinary
Mike A. Lund, Akshaykumar Salimath, Kjetil M. D. Hals
Summary: The study theoretically investigates the ac spin pumping of noncollinear antiferromagnets, demonstrating that the spin orientation of the pumped spin current can be controlled by exciting different spin-wave modes. Additionally, it is found that the three spin-wave bands of the kagome antiferromagnet generate spin currents with mutually orthogonal polarization directions.
Article
Multidisciplinary Sciences
Sergi Martin-Rio, Carlos Frontera, Alberto Pomar, Lluis Balcells, Benjamin Martinez
Summary: In this study, a simple method is proposed to suppress the contribution of spin rectification effects to the inverse spin Hall effect by adjusting the sample width. Experimental results and numerical simulations confirm the effectiveness of this method.
SCIENTIFIC REPORTS
(2022)
Article
Physics, Multidisciplinary
V. Fernandez Becerra, Mircea Trif, Timo Hyart
Summary: We study the properties of semiconducting nanowires with induced superconductivity and ferromagnetism, and find that spin pumping is quantized in the topologically nontrivial phase while charge pumping is not. In long topologically nontrivial nanowires, there is a one-to-one correspondence between quantized conductance, entropy change, and spin pumping. The observation of correlated and quantized peaks in conductance, entropy change, and spin pumping would provide strong evidence of Majorana zero modes.
PHYSICAL REVIEW LETTERS
(2023)
Article
Quantum Science & Technology
Biswajit Sahoo, Koustuv Roy, Pushpendra Gupta, Abhisek Mishra, Biswarup Satpati, Braj Bhusan Singh, Subhankar Bedanta
Summary: The study focuses on spin pumping and inverse spin Hall effect in an IrO2/CoFeB system. By analyzing the angular dependence of ISHE voltage, it identifies the significant contribution of spin pumping to the ISHE signal. The research shows that polycrystalline IrO2 thin film exhibits high spin Hall conductivity and spin Hall angle comparable to Pt.
ADVANCED QUANTUM TECHNOLOGIES
(2021)
Article
Multidisciplinary Sciences
X. Liu, P. Liu, H. C. Yuan, J. Y. Shi, H. L. Wang, S. H. Nie, F. Jin, Z. Zheng, X. Z. Yu, J. H. Zhao, H. B. Zhao, G. Lupke
Summary: Spin angular momentum transfer in magnetic bilayers offers the potential for ultrafast and low-loss operation in next-generation spintronic devices. In this study, field- and temperature-dependent measurements were conducted on the magnetization precessions in Co2FeAl/(Ga,Mn)As using time-resolved magneto-optical Kerr effect. The results indicate an enhanced dynamic exchange coupling between the two ferromagnetic layers due to reinforced spin pumping at resonance, as well as a primary contribution from the ferromagnetism in (Ga,Mn)As.
SCIENTIFIC REPORTS
(2022)
Article
Materials Science, Multidisciplinary
K. Fukuzawa, T. Kato, M. Matsuo, T. Jonckheere, J. Rech, T. Martin
Summary: In this study, we theoretically investigate the process of spin pumping from a ferromagnetic insulator (FI) into a carbon nanotube (CNT). Using the bosonization method, we derive the Gilbert damping induced by the FI/CNT junction, which can be measured through ferromagnetic resonance. We find that the increase in Gilbert damping shows a temperature dependence characteristic of a Luttinger liquid and is highly sensitive to the Luttinger parameter of the spin sector for a clean interface. We also discuss the experimental implications of our findings based on numerical estimates using realistic parameters.
Article
Optics
Xiaoyu Shi, Wanting Song, Ningning Liang, Dan Guo, Kaiyue Shen, Tianrui Zhai
Summary: This study reveals the crucial role of the pump boundary in the mode interaction and emission characteristics of diffusive random lasers. By increasing the ratio between the square root of the pump area and the circumference of the pump region, the strongly correlated nonresonant laser mode with a continuous spectral distribution is transformed into an independent resonant laser mode with a discrete frequency distribution. A critical ratio of 5.76 is demonstrated as the transition point for pump spots with arbitrary shapes. This pump strategy provides a universal guideline for regulating laser modes in diffusive RL systems that can be applied to multifunctional lasers to clarify the behavior of light in disordered structures.
LASER & PHOTONICS REVIEWS
(2023)
Article
Physics, Fluids & Plasmas
P. L. Garrido
Summary: We study the behavior of stationary nonequilibrium two-body correlation functions for diffusive systems with equilibrium reference states. We describe the dynamic of the system using coupled Langevin equations with white noises. We decompose the correlations into known local equilibrium part and a nonequilibrium behavior, and solve the differential equations for the nonequilibrium part through a perturbative expansion. The results show that fluctuations are dominated by local equilibrium up to the second order in the perturbative expansion around the equilibrium state.
Article
Physics, Applied
Bivas Rana, Collins Ashu Akosa, Katsuya Miura, Hiromasa Takahashi, Gen Tatara, YoshiChika Otani
PHYSICAL REVIEW APPLIED
(2020)
Article
Physics, Applied
Christian Ortiz Pauyac, Collins Ashu Akosa, Gen Tatara, Mairbek Chshiev, Alan Kalitsov
Summary: This study investigates the thermal spin torque induced by the spin-dependent Seebeck effect in double-barrier tunnel junctions, revealing different dominant terms in thermal spin torque under different combinations of electrodes and barriers. Quantum resonant tunneling through resonance states below the Fermi level is proposed as a method to achieve higher spin-torque efficiencies.
PHYSICAL REVIEW APPLIED
(2021)
Article
Physics, Multidisciplinary
Gen Tatara
Summary: The spin Hall effect at finite wave vector in a ferromagnetic conductor is investigated by studying the spin density as a linear response to an applied electric field. The cases of a spin-orbit interaction due to random impurities and a localized Rashba interaction are considered. It is found that the spin Hall effect shows a strong response for wave vectors less than or equal to 2k(F), confirming its local nature.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2022)
Article
Physics, Multidisciplinary
Gen Tatara
Summary: This study investigates the spin accumulation induced by an electric field in a chiral electron system using the linear response theory. It is found that the spin response function has a spatially uniform component, resulting in nonlocal spin generation, due to the chiral angular momentum generation effect. The decay length of the spin profile is proportional to the electron's elastic mean free path.
JOURNAL OF THE PHYSICAL SOCIETY OF JAPAN
(2022)
Article
Physics, Applied
Mana Miyata, Jun-ichiro Ohe, Gen Tatara
Summary: Manipulation of the topological charge in a skyrmion structure can be achieved by applying circularly polarized light, which arises from the coupling of light helicity and topological charge.
PHYSICAL REVIEW APPLIED
(2022)
Article
Materials Science, Multidisciplinary
Guanxiong Qu, Gen Tatara
Summary: In this study, we investigate the intrinsic OHC and SHC in a bismuth semimetal and report a notable difference between their anisotropy. We do not observe a substantial correlation between OHC and SHC, disproving the correlation in a strong SOC regime. We argue that the huge SHC in a Bi semimetal is attributed to its gigantic SOC which strongly affects the hybridization of the p orbitals.
Article
Materials Science, Multidisciplinary
X. -g. Wang, L. Chotorlishivil, G. Tatara, A. Dyrdal, Guang-hua Guo, V. K. Dugaev, J. Barnas, S. S. P. Parkin, A. Ernst
Summary: In this study, we comprehensively analyze the phason excitations of a skyrmion lattice in synthetic antiferromagnets using three different methods. We propose an analytical model based on three coupled helices and discover a linear gapless mode in the skyrmion lattice. The results are supported by micromagnetic simulations. We also consider the orbital angular momentum and spin pumping current associated with phason excitations.
Article
Materials Science, Multidisciplinary
Atsuo Shitade, Gen Tatara
Summary: The article discusses the spin Hall effect in the presence of spin-orbit couplings, introduces a general method for calculating the spin response to an electric-field gradient, and explores specific model responses.
Article
Materials Science, Multidisciplinary
Gen Tatara
Summary: This study theoretically investigates electron spin transport in a disordered ferromagnetic metal from a hydrodynamic perspective, with a focus on the role of electron vorticity. The spin-resolved momentum flux density and motive force are found to be characterized by troidal moments, showing effective driving fields when considering anomalous or spin Hall effects. Natural couplings of spin-vorticity and magnetizationvorticity arise as conservative forces driven by toroidal moments, along with the existence of nonconservative forces.
Article
Physics, Multidisciplinary
R. M. Otxoa, R. Rama-Eiroa, P. E. Roy, G. Tatara, O. Chubykalo-Fesenko, U. Atxitia
Summary: This study reveals the potential of antiferromagnetic solitons as nano energy carriers, with the ability to absorb, transport, and release energy. Their relativistic kinematics and topological classification allow for high-speed, selective energy release back into the medium.
PHYSICAL REVIEW RESEARCH
(2021)
Article
Physics, Multidisciplinary
Hiroshi Funaki, Riki Toshio, Gen Tatara
Summary: A hydrodynamic theory for an electron system with anomalous Hall effect is developed, showing the induction of an additional anomalous Hall effect by vorticity near boundaries. The coupling between vorticity of electric current and magnetization is demonstrated to generate pressure from nonuniform vorticity. Hall viscosity and relaxation forces contribute to calculating nonuniform flows near boundaries and an additional Hall force.
PHYSICAL REVIEW RESEARCH
(2021)
Article
Physics, Multidisciplinary
Hiroshi Funaki, Gen Tatara
Summary: In this study, a hydrodynamic theory based on field theory is proposed to describe a chiral electron system with a Weyl spin-orbit interaction. By evaluating the momentum flux density in response to an electric field, an equation of motion for the orbital angular momentum is derived. It is found that the chiral nature induces dynamic bulk angular momentum generation by responding to the applied field with a global torque, and the steady-state angular momentum is calculated considering rotational viscosity.
PHYSICAL REVIEW RESEARCH
(2021)
Article
Physics, Multidisciplinary
Gen Tatara, Collins Ashu Akosa, Ruben M. Otxoa de Zuazola
PHYSICAL REVIEW RESEARCH
(2020)
Article
Physics, Multidisciplinary
Frederico Sousa, Gen Tatara, Aires Ferreira
PHYSICAL REVIEW RESEARCH
(2020)
Article
Materials Science, Multidisciplinary
S. A. Obadero, Y. Yamane, C. A. Akosa, G. Tatara