Theoretical Studies on Spin-Dependent Conductance in FePt/MgO/FePt(001) Magnetic Tunnel Junctions

The spin-dependent transport properties of FePt/MgO/FePt(001) magnetic tunnel junctions have been investigated on the basis of first-principles electronic structure calculations. The totally symmetric Delta₁-band predominantly contributes to the tunneling conductance for both the majority and the minority-spin channels. In the parallel magnetization configuration, the tunneling conductance via the majority-spin channel shows almost the same values for the junctions with the Fe- and Pt-terminated interfaces. On the other hand, the tunneling conductance via the minority-spin channel for the Fe-terminated interface is two orders of magnitude smaller than that through the Pt-terminated interface. The tunneling magnetoresistance ratio evaluated for the junction with the Fe-terminated interface exceeds 380%, which is in contrast to about 70% for that with the Pt-terminated interface.