Ferromagnetic exchange interaction between hard and soft ferromagnetic layers through ZnS semiconductor

Abstract We experimentally evidenced the presence of an indirect exchange coupling between hard and soft ferromagnetic electrodes through a ZnS barrier in magnetic tunnel junctions. For a 2 nm thick ZnS barrier, a negative shift of about –25 Oe is observed in asymmetric magnetization minor loop. This is attributed to a ferromagnetic interaction between the CoFe/Fe soft bilayer and the thick CoFe layer. The amplitude of the observed shift decreased as the thickness of the ZnS barrier increased, which agrees with theoretical models that the exchange interaction is mediated by spin polarized tunneling.