12,000

We have over 12,000 students, from over 100 countries, within one of the safest campuses in the UK

93%

93% of Lancaster students go into work or further study within six months of graduating

Home > Research > Publications & Outputs > Subgap transport in ferromagnet-superconductor ...
View graph of relations

« Back

Subgap transport in ferromagnet-superconductor junctions due to magnon-assisted Andreev reflection

Research output: Contribution to journalJournal article

Published

Article number024519
Journal publication date1/01/2002
JournalPhysical review b
Journal number2
Volume65
Number of pages15
Pages-
Original languageEnglish

Abstract

We propose a process of magnon-assisted Andreev reflection at a ferromagnetic metal-superconductor (FS) interface, which consists of the simultaneous injection of a Cooper pair from the superconductor and the emission of a magnon inside the ferromagnet. At low temperature this process represents an additional channel for subgap transport across an FS interface, which lifts restrictions on the current resulting from the necessity to match spin-polarized current in the ferromagnet with spinless current in the superconductor. For a junction between a superconductor and a ferromagnet with an arbitrary degree of polarization, the inelastic magnon-assisted Andreev reflection process would manifest itself as a nonlinear addition to the I(V) characteristics, which is asymmetric with respect to the sign of the bias voltage and is related to the density of states of magnons in the ferromagnet. Expressions for the subgap I(V) characteristics are given for arbitrary interfacial quality while the limiting cases of uniformly transparent and disordered interfaces are discussed in detail.