Angular Dependence Of Giant Magnetoresistance Research Articles

Correlation of the angular dependence of spin-transfer torque and giant magnetoresistance in the limit of diffusive transport in spin valves

Angular variation in giant magnetoresistance and spin-transfer torque in metallic spin-valve heterostructures is analyzed theoretically in the limit of diffusive transport. It is shown that the spin-transfer torque in asymmetric spin valves can vanish in noncollinear magnetic configurations, and such a nonstandard behavior of the torque is generally associated with a nonmonotonic angular dependence of the giant magnetoresistance, with a global minimum at a noncollinear magnetic configuration.

Angular dependence of giant magnetoresistance in spin-valve sandwiched structures

By extending the semiclassical approach of Camely and Barnas, we quantitatively analyze the angular dependence of giant magnetoresistance (GMR) in Permalloy-based spin-valve structures. In the case of purely diffusive scattering at the outer boundaries of NiFe/Cu/NiFe trilayers, we derive an explicit expression that shows the linear variation of GMR with the cosine of the angle between the magnetizations in the adjacent ferromagnetic layers. In the presence of specular scattering (R) at the outer boundaries, the angular variation is found to be approximately linear for the case of $R=0.5,$ and nonlinear when $R=1.$ The present approach is also applicable to other spin-valve systems.

Angular dependence of giant magnetoresistance in magnetic multilayers

Angular dependence of giant magnetoresistance in magnetic multilayers

Angular dependence of giant magnetoresistance in a superlattice.

Most discussions of giant magnetoresistance (GMR) have focused on collinear cases where the magnetizations in adjacent layers are either parallel or antiparallel. To explore the relative importance of the superlattice potential and of the impurity scattering on the angular dependence of GMR, we calculate the electrical resistivity for noncollinear magnetizations. The electronic structure of the superlattice is modeled by a Kronig-Penney potential. When the magnetizations of the adjacent layers are neither parallel nor antiparallel, spinor forms of Bloch states and dispersion relations are derived. Then the conductivity as a function of the angle between magnetization directions of adjacent layers is calculated in the homogeneous limit where the mean free path is much larger than the layer thickness. We find the angular dependence of the resistivity and hence of the GMR for current in the plane of layers and perpendicular to the plane of the layers depends on the spin-dependent superlattice potential, and the details of the scattering potential. \textcopyright{} 1996 The American Physical Society.

Quantum singularities in the angular dependence of giant magnetoresistance in ultrathin ferromagnetic sandwiches

We present an analytical quantum statistical theory of the angular variation of the giant magnetoresistance (GMR) in thin ferromagnetic sandwiches (current flowing in the plane of the layers). Both spin-dependent scattering of conduction electrons and the existence of spin-dependent potential barriers between the successive layers are taken into account. We show that quantum singularities can arise in the variation of the electrical resistivity of the structure with the angle between the magnetizations in the ferromagnetic layers. These singularities result from the quantization of the momentum of electrons in the direction perpendicular to the plane of the layers.