Spin-polarized quasiparticle transport in ferromagnet-d-wave-superconductor junctions with a {110} interface

Within a scattering framework, a theoretical study is presented for the spin-polarized quasiparticle transport in ferromagnet-d-wave-superconductor junctions with {110} interface. We find that the subgap conductance behaviors are qualitatively different from a nonmagnetic case, due to the modification of Andreev reflection by the exchange field in the ferromagnet, and can also be significantly different from those of a ferromagnets-wave junction because of the sign change of the d-wave order parameter along the {110} direction of the crystal. For a ballistic ferromagnet-d-wave-superconductor junction, a zero-bias conductance minimum is achieved. In addition, a conductance maximum at finite bias can also be evolved by interfacial scattering. For a normal-metal-ferromagnet-d-wave-superconductor junction, conductance resonances are predicted. [S0163-1829(99)10213-3].