Theoretical perspectives on transport of charge across ferromagnet/superconductor junction: New approach to verify quality of junction

Abstract

A new approach to verify the quality of the magnetic tunnel junction between a ferromagnet and a superconductor single junction (FM/SC) is presented. In this work, we theoretically studied the tunneling conductance spectra of a FM/SC using the scattering method under a free electron approximation model in a two dimensional system. The main area of interest was the physical properties of a junction that was defined by the Dirac delta potential. It was found that the kinks occurring at the energy scale of the ferromagnetic material were suppressed when increasing the strength of the interfacial scattering, but they dominated at the metallic limit of the junction, where the potential strength at the junction was weak. Experimentally, this feature can be used to identify the quality of a ferromagnetic and superconductor junction by considering the shape of those kinks. Furthermore, when the effect of interfacial scattering Z and the conductivity mismatch on the conductance spectra were considered and compared, we found that the conductance spectra of the junction was sensitive to a change in the strength of Z.