Andreev Reflection in Narrow Ferromagnet/Superconductor Point Contacts

摘要

The Andreev reflection of narrow ferromagnet/superconductor point contacts istheoretically studied. We show that the conductance quantization depends onwhether the contact region is superconducting or ferromagnetic as well as onthe strength of the exchange field in the ferromagnet. The Andreev reflectionof the ferromagnetic contact is more suppressed than that of thesuperconducting contact. We also show that the conductance-voltage curve has abump at zero bias-voltage if there is no interfacial-scattering. On thecontrary, the conductance-voltage curve shows a dip if the system has aninterfacial-scattering.