Biao Jin, Gang Su^a and Qing-Rong Zheng

College of Physical Sciences, Graduate School of the Chinese Academy of Sciences, P.O. Box 3908, Beijing 100039, China

(Received 7 May 2004; accepted 17 August 2004)

Abstract:

    Spin-dependent transport in ferromagnet/superconductor/ferromagnet double-tunnel junctions is revisited by taking both the spin and quasiparticle charge imbalances into account. It is shown that even a small quasiparticle charge imbalance can lead to remarkable changes of the superconducting and transport properties. In particular, it is found that a first-order phase transition from an inhomogeneous superconducting state to the normal state will take place in both the antiparallel and parallel alignments of magnetizations, as the bias voltage is increased to a critical value. A quantum critical point is specified. © 2004 American Institute of Physics. [DOI: 10.1063/1.1804247]