TUNNELING MAGNETORESISTANCE IN FERROMAGNET INSULATOR/FERROMAGNET JUNCTIONS/

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