We investigate effects of spin-orbit splitting on electronic transport in a spin valve consisting of a large quantum dot defined on a two-dimensional electron gas with two ferromagnetic contacts. In the presence of both structure and bulk inversion asymmetry a giant anisotropy in the spin-relaxation times has been predicted. We show how such an anisotropy affects the electronic transport proper...

Title of dissertation: SPIN INJECTION AND DETECTION IN COPPER SPIN VALVE STRUCTURES Samir Garzón, Doctor of Philosophy, 2005 Dissertation directed by: Richard A. Webb Department of Physics We report measurements of spin injection and detection in a mesoscopic copper wire from which the electron spin relaxation time and the spin current polarization in copper can be found. Spin injection is real...

A large spin accumulation due to the electrical spin injection has been observed in Permalloy-silver lateral spin-valve structures. The observed resistance change is the largest among the reported metallic lateral spin valves with Ohmic junctions. The spin-diffusion length deduced from the experimental results is also found to be the longest among the normal metals reported so far. All the resu...

MRAM has received a great deal of attention in recent years for its potential to become a universal memory capable of nonvolatility, infinite cycleability, fast switching speeds, high density, and low cost. However, the limitations of conventional design architectures have made MRAM difficult to realize. In this work, a new annular currentperpendicular-to-plane (CPP) giant magnetoresistive (GMR...

A theory of spin-polarized transport in inhomogeneous magnetic semiconductors is developed and applied to magnetic/nonmagnetic p-n junctions. Several phenomena with possible spintronic applications are predicted, including spin-voltaic effect, spin valve effect, exponential and giant magnetoresistance. It is demonstrated that only nonequilibrium spin can be injected across the space-charge regi...

Spin-momentum helical locking is one of the most important properties of the nontrivial topological surface states (TSS) in 3D topological insulators (TIs). It underlies the iconic topological protection (suppressing elastic backscattering) of TSS and is foundational to many exotic physics (e.g., majorana fermions) and device applications (e.g., spintronics) predicted for TIs. Based on this spi...

We present switching field distributions of spin-transfer assisted magnetization reversal in perpendicularly magnetized Co/Ni multilayer spin-valve nanopillars at room temperature. Switching field measurements of the Co/Ni free layer of spin-valve nanopillars with a 50 nm× 300 nm ellipse cross section were conducted as a function of current. The validity of a model that assumes a spin-current d...

We show that spin anisotropy can be transferred to an isotropic system by transport of a spin-quadrupole moment. We derive the quadrupole moment current and continuity equation and study a spin-valve structure consisting of two ferromagnets coupled to a quantum dot probing an impurity spin. The quadrupole backaction on their coupled spin results in spin torques and anisotropic spin relaxation w...

In systems with strong spin-orbit coupling, the relationship between spin transfer torque and the divergence of the spin current is generalized to a relation between spin transfer torques, total angular momentum current, and mechanical torques. In ferromagnetic semiconductors, where the spin-orbit coupling is large, these considerations modify the behavior of the spin transfer torques. One exam...

The hot electron magnetotransport in a spin-valve transistor has been theoretically explored at finite temperatures. We have explored the parallel and anti-parallel collector current changing the relative spin orientation of the ferromagnetic layers at finite temperatures. In this model calculations, hot electron energy redistribution due to spatial inhomogeneity of Schottky barrier heights and...