Bias dependence of the tunneling magnetoresistance in double spin-filter junctions

摘要

With the intention of providing reference materials for research, manufacture and application of magnetoresistance devices, we calculate the dependences of tunneling magnetoresistance (TMR) in a NM/FI/FI/NM double spin-filter junction (DSFJ) on the bias (voltage) and, secondarily, on the thickness, barrier height and molecular field of FIs here the NM and FI represent the nonmagnetic electrode and the ferromagnetic insulator (semiconductor) spacer, respectively. Our results show that for the TMR of the DSFJ besides its very high value it does not decrease monotonously and rapidly with a rise of bias, but increases slowly at first and then decreases after a maximum value is reached. This feature is in distinct contrast to the ordinary magnetic tunnel junction FM/NI/FM and thus facilitates the application of the DSFJ as a magnetoresistance device here FM and NI denote the ferromagnetic electrode and the nonmagnetic insulator (semiconductor) spacer, respectively. The influence of the thickness, barrier height and, especially, the molecular field of FIs on TMR and its bias dependence is also not negligible.