磁性隧道结隧穿电导和磁电阻的研究

针对由一平面磁性势垒隔开的两铁磁性金属电极构成的磁性隧道结,基于自由电子近似并利用传递矩阵方法计算了其零偏压下的隧穿电导、自旋极化率和隧穿磁阻比率,研究表明隧道结的磁结构对TC(隧穿电导)和TMR(隧穿磁阻)的值有很大的影响,当两磁性电极分子场方向相同,且都与势垒层分子场反平行时,TC数值达到最大,两者平行时,TC的数值最小,同时还分析了分子场的相对取向等对磁性隧道结自旋极化电子输运性质的影响。研究结果对自旋电子器件的设计具有一定的指导意义。

Study of Tunneling Conductance and Magnetoresistance in Magnetic Junctions

For a magnetic tunneling junction with ferromagnetic metal/magnetic potential barrier layer/ferromagnetic metal structure,tunneling conductance,spin polarization and tunneling magneto resistance rate under zero bias voltage are calculated,using the transfer matrix method in a quasi-free electron model.The results show that TC and TMR strongly depend on the magnetization configuration of the junction.The TC reaches its maximums when the magnetic moments of the two electrodes are parallel to each other but antiparallel to that of the barrier,whereas the minimums appears when the magnetic moments of both electrodes and the barrier are parallel.The impact of molecular field orientation on tunneling of electrons is analyzed.It exhibits useful instructions for the design of spin electronic devices.