CALCULATION OF THE CANTING ANGLE DEPENDENCE OF THE RESISTIVITY IN CU-VERTICAL-BAR-CO SPIN VALVES

We consider the in-plane electrical conductivity of a spin valve, spec ifically, a system consisting of a copper slab between two cobalt slab s. We calculate the dependence of the resistivity on the canting angle , where the canting angle theta is defined as the angle between the ma gnetization vectors of two ferromagnetic slabs in a spin valve. To cal culate the electronic structure, we utilize the layer-KKR formalism. E lectron scattering by impurities, phonons, magnons, etc. is modeled us ing a layer and spin-dependent complex self-energy. Scattering rates a re chosen to match Cu and Co resistivities. We assume a spin asymmetry scattering rate factor of 7 in Co, matching the Fermi-level minority- to-majority density-of-states ratio. No additional interfacial scatter ing is included. The nonlocal layer dependent conductivity is calculat ed using the Kubo-Greenwood formula for systems consisting of 3 and 7 monolayer fcc (111) Cu slabs in Co. We find electron channeling in Cu dominates the conductivity and at theta=pi/2 the resistivity is increa sed by 4.9% and 2.3% from a linear 1-cos theta dependence. We find gia nt magnetoresistive GMR values of 64% and 36% for 3 and 7 monolayers o f Cu, respectively. (C) 1997 American Institute of Physics.