Andreev transport through single-molecule magnets

Abstract

The Andreev transport through a large-spin magnetic molecule, such as a single molecular magnet, attached to superconducting and ferromagnetic leads is studied theoretically by means of the real-time diagrammatic technique. It is shown that due to the proximity effect, molecular Andreev bound states form in the system, with energies depending on the intrinsic parameters of the molecule. We study the spin-resolved Andreev current, conductance, and tunnel magnetoresistance in both the linear and nonlinear response regimes and find regions of negative differential conductance, as well as either enhanced or negative tunnel magnetoresistance. The mechanisms leading to those effects are thoroughly discussed. It is also shown that the tunnel magnetoresistance can provide information about particular spin multiplets responsible for the Andreev reflection processes.