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J. Shibata

Publications and source records attributed to J. Shibata.

3 recordsLinked to original sources
arXiv2009

Microscopic Theory of Current-Spin Interaction in Ferromagnets

Interplay between magnetization dynamics and electric current in a conducting ferromagnet is theoretically studied based on a microscopic model calculation. First, the effects of the current on magnetization dynamics (spin torques) are studied with special attention to the "dissipative" torques arising from spin-relaxation processes of conduction electrons. Next, an analysis is given of the "spin motive force", namely, a spin-dependent 'voltage' generation due to magnetization dynamics, which is the reaction to spin torques. Finally, an attempt is presented of a unified description of these effects.

cond-mat.mes-hall↗
arXiv2006

Vortex motion in chilarity-controlled pair of magnetic disks

We investigate the influence of the vortex chirality on the magnetization processes of a magnetostatically coupled pair of magnetic disks. The magnetic vortices with opposite chiralities are realized by introducing asymmetry into the disks. The motion of the paired vortices are studied by measuring the magnetoresistance with lock-in resistance bridge technique. The vortex annihilation process is found to depend on the moving directions of the magnetic vorticies. The experimental results are well reproduced by the micromagnetic simulation.

cond-mat.mtrl-sci↗
arXiv2006

Microscopic Calculation of Spin Torques and Forces

Spin torques, that is, effects of conduction electrons on magnetization dynamics, are calculated microscopically in the first order in spatial gradient and time derivative of magnetization. Special attention is paid to the so-called β-term and the Gilbert damping, α, in the presence of electrons' spin-relaxation processes, which are modeled by quenched magnetic impurities. Two types of forces that the electric/spin current exerts on magnetization are identified based on a general formula relating the force to the torque.

cond-mat.mes-hall↗