Anh Kiet Nguyen

Giant Current-Driven Domain Wall Mobility in (Ga,Mn) As

We study theoretically hole current-driven domain wall dynamics in (Ga,Mn)As. We show that the spin-orbit coupling causes significant hole reflection at the domain wall, even in the adiabatic limit when the wall is much thicker than the Fermi wavelength, resulting in spin accumulation and mistracking between current-carrying spins and the domain wall magnetization. This increases the out-of-plane nonadiabatic spin-transfer torque and consequently the current-driven domain wall mobility by 3 to 4 orders of magnitude. Trends and magnitude of the calculated domain wall current mobilities agree with experimental findings.

Time lapse refraction seismic - a tool for monitoring carbonate fields?

Time lapse refraction seismic has potential for accurate estimation of reservoir velocity changes. Careful processing using rugby-shaped fk-filters, followed by RMS amplitude analysis versus offset is used. Typically, the RMS amplitude level peaks at an offset values slightly larger than the critical offset. By measuring the shift in this peak between the base line and monitor survey, it is possible to estimate the velocity change in the reservoir layer.

Intrinsic coupling between current and domain wall motion in (Ga,Mn)As.

We consider current-induced domain wall motion and, the reciprocal process, moving domain wall-induced current. The associated Onsager coefficients are expressed in terms of scattering matrices. Uncommonly, in (Ga,Mn)As, the effective Gilbert damping coefficient alphaw and the effective out-of-plane spin-transfer torque parameter betaw are dominated by spin-orbit interaction in combination with scattering off the domain wall, and not scattering off extrinsic impurities. Numerical calculations give alphaw approximately 0.01 and betaw approximately 1 in dirty (Ga,Mn)As. The extraordinarily large betaw parameter allows experimental detection of current or voltage induced by domain wall motion in (Ga,Mn)As.

Onsager loop transition and first-order flux-line lattice melting in high- T c superconductors

Monte Carlo simulations in conjunction with finite-size scaling analysis are used to investigate the

Intrinsic domain-wall resistance in ferromagnetic semiconductors

(H,T)

Phase transitions in isotropic extreme type-II superconductors

-phase diagram in uniaxial anisotropic high-

Vortex-Loop Unbinding and Flux-Line Lattice Melting in Superconductors

{T}_{c}

Effective magnetic monopoles and universal conductance fluctuations.

superconductors, both in zero magnetic field

Enhanced subsurface response for marine CSEM surveying

(B=0)

External control of a metal-insulator transition in GaMnAs wires.

and in intermediate magnetic fields