Andreev reflection effect on spin-polarized transport in ferromagnet/superconductor/ferromagnet double tunnel junctions

Abstract

We take the Andreev reflection into account and apply a quantum-mechanical approach to studying spin-polarized transport in a ferromagnet/superconductor/ferromagnet double tunnel junction and its effect on superconductivity in the superconductor. It is found that in the presence of the Andreev reflection the tunneling magnetoresistance in the double tunnel junction depends strongly on barrier strength. In the antiferromagnetic alignment of the magnetizations, an increase in bias voltage will give rise to a first-order transition from the superconducting state to a normal one.