Independent magnetization behavior of a ferromagnetic   metal/semiconductor hybrid system
  We report the discovery of an effect where two ferromagnetic materials, one semiconductor ((Ga,Mn)As) and one metal (permalloy), can be directly deposited on each other and still switch their magnetization independently. We use this independent magnetization behavior to create various resistance states dependent on the magnetization direction of the individual layers. At zero magnetic field a two layer device can reach up to four non-volatile resistance states. 
S. Mark, C. Gould, K. Pappert, J. Wenisch, K. Brunner, G. Schmidt, and   L.W. Molenkamp