多铁耦合隧穿磁阻效应研究

Magnetic tunnel junction has widely application in data storage, sensor and so on. Recently people tried a lot to integrate ferroelectric and ferromagnetic in one device, so called multiferroic device. It maybe realize the multi free degree control of magnetic transport by coupling the ferroelectric and ferromagnetic effects. Here a non-equilibrium Green-function model is employed to investigate the spin transport properties in a multiferroic magnetic tunnel junction (Mn,Zn)O/(Li,Zn)O/(Mn,Zn)O. It shows that the large tunneling magnetic (TMR) can be achieved in low temperature and low bias. With increasing temperature or bias, the TMR deceases rapidly due to the similars electrons distribution in spin up and spin down sub-bands. The ferroelectric dipole direction can control the TMR at low bias. Due to the ferroelectric dipole, a barrier is formed in the interface between the emittor and the space layer for the dipole left or the collector and the space layer for the dipole right. And the barrier in the interface between the collector and space layer can be lowed more easyly by the bias that the one between the emittor and the space layer. High temperature leads rapidly dampling for both spin polarization and TMR.