The tunneling magnetic resistance in ferromagnetic junctions with spin-filter composite tunnel barriers

Abstract

Within the framework of the free-electron model, the tunneling magnetoresistance (TMR) in FM/I/SF/NM quasi-magnetic tunnel junctions (QMTJ) is investigated. FM, NM, I and SF represent the ferromagnetic metal, nonmagnetic metal, insulator and spin-filter barrier, respectively. Our results show that due to the spin-filtering effect in SF potential barriers, the FM/I/SF/NM can obtain relatively stabilized TMR in higher bias region when it has higher potential height and thicker SF barrier. And, for obtaining large TMR, the total thickness of the barrier region would be carefully selected as the influence of the supplementary I layer.