A theoretical study of the effect of electronic structures of ferromagnets on giant magnetoresistance

Abstract

We explain the spin-dependent electronic and physical properties of conduction electrons by using the magnitude of exchange splitting of the spin-up and the spin-down half bands in the band structure. This is done by calculating the transmission amplitudes by using a transfer-matrix method and, consequently, evaluating the ballistic spin-transport and the giant magnetoresistance (GMR) of the current perpendicular to the plane (CPP) by using the circuit theory for a ferromagnetic metal/noble metal/ferromagnetic metal simple spin valve. As a result, most transmission probabilities with transverse modes show sawtooth-like oscillations due to the strong intersubband scattering at the potential steps. Besides, the asymmetric spin-dependent potential profile induced by exchange splitting causes a stronger fluctuation in the case of spin-down transmission coefficients than it does in the case of spin-up transmission coefficients. Moreover, these oscillations disappear in the case of the spin-up transmission probabilities, but the oscillations in the spin-down case become more pronounced with exchange splitting, which, depending on exchange splitting, causes a rise in the spin-polarization and the GMR.