Soon-Wook Jung

Current-Induced Magnetic Domain-Wall Motion by Spin Transfer Torque

The spin transfer torque generated by a spin-polarized current can induce the shift of the magnetic domainwall position. In this work, we study theoretically the current-induced domain-wall motion by using the collective coordinate approach [Gen Tatara and Hiroshi Kohno, Phys. Rev. Lett. 92, 86601 (2004)]. The approach is extended to include not only the domain-wall position and the polarization angle changes but also the domainwall width variation. It is demonstrated that the width variation affects the critical current.

Spin polarization amplification within nonmagnetic semiconductors at room temperature

We demonstrate theoretically that the spin polarization of currents can be electrically amplified within nonmagnetic semiconductors by exploiting the fact that the spin current, compared to the charge current, is weakly perturbed by electric driving forces. As a specific example, we consider a

Spin-current-induced charge current

T

On the development of a compact toroid injector at the University of Illinois at Urbana-Champaign

-shaped current branching geometry made entirely of a nonmagnetic semiconductor, where the current is injected into one of the branches (input branch) and splits into the other two branches (output branches). We show that when the input current has a moderate spin polarization, the spin polarization in one of the output branches can be higher than the spin polarization in the input branch and may reach 100% when the relative magnitudes of current-driving electric fields in the two output branches are properly tuned. The proposed amplification scheme does not use ferromagnets or magnetic fields, and does not require a low temperature operation; providing an efficient way to generate a highly spin polarized current in nonmagnetic semiconductors at room temperature.

Measurements of the ion temperature and ion energy distribution in a linear pulsed plasma-material interaction test stand

We show that the injection of a pure spin current (not accompanied by charge current) into a ring can induce a circulating charge current in the ring, provided that transport coefficients of the ring are spin dependent and inhomogeneous. As an example, we consider a hybrid ferromagnet\char21{}normal-metal ring system and calculate the magnitude of the charge current induced by the pure spin current injection. This phenomenon may have relevance for spintronic applications.