In a stack of a ferromagnetic semiconductor, a tunnel barrier, and a non-magnetic metal, a strong tunnelling magneto-resistance can occur. The resistance is due to the change in the density of states in the ferromagnet with changing of the direction of the magnetization with respect to the lattice. In a layers stack with two ferromagnetic layers the effect can be strongly enhanced.
-C. Gould, C. Ruster, T. Jungwirth, E. Girgis, G.M. Schott, R. Giraud, K. Brunner, G. Schmidt and L.W. Molenkamp
Tunnelling Anisotropic Magneto-resistance: A spin-valve like tunnel magneto-resistance using a single magnetic layer
Phys. Rev. Lett. 93, 117203 (2004)
-C. Ruster, C. Gould, T. Jungwirth, J. Sinova, G. M. Schott, R. Giraud, K. Brunner, G. Schmidt, and L.W. Molenkamp
Very large Tunnelling Anisotropic Magneto-resistance of a (Ga,Mn)As/GaAs/(Ga,Mn)As stack
Phys. Rev. Lett. In press