Tunneling magnetoresistance in ferromagnet/insulator/ferromagnet junctions

Abstract

A δ-type potential with complex prefactor is modeled on the tunneling barrier of a thin insulator (I) film separating two ferromagnetic (FM) films. By matching value and slope of wave functions across the tunneling barrier of a FM/I/FM junction, we obtain a general expression for tunneling conductance as a function of relative orientation θ between magnetizations of the two ferromagnets, barrier height and interface roughness. It is shown that the magnitude of tunneling magnetoresistance is strongly dependent on θ, but much less affected by the barrier height and the interface roughness.