Ferromagnetic features on zero-bias conductance peaks in ferromagnet/insulator/superconductor junction

TL;DR

This paper develops a formula for tunneling conductance in ferromagnet/insulator/superconductor junctions with opposite spin pairing, highlighting how different ferromagnetic mechanisms influence zero-bias conductance peaks and can reveal underlying ferromagnetism mechanisms.

Contribution

It introduces a new formula for tunneling conductance considering effective mass mismatch and compares ferromagnet types in superconductor junctions.

Findings

Zero-bias conductance peaks differ between ferromagnet types.

Normalization method affects conductance spectra.

Measurements can reveal ferromagnetism mechanisms.

Abstract

We present a formula for tunneling conductance in ballistic ferromagnet/ferromagnetic insulator/superconductor junctions where the superconducting state has opposite spin pairing symmetry. The formula can involve correctly a ferromagnetism has been induced by effective mass difference between up- and down-spin electrons. Then, this effective mass mismatch ferromagnet and standard Stoner ferromagnet have been employed in this paper. As an application of the formulation, we have studied the tunneling effect for junctions including spin-triplet p-wave superconductor. The conductace spectra show a clear difference between two ferromagnets depending upon the way of normalization of the conductance. Especially, a essential difference is seen in zero-bias conductance peaks reflecting characteristics of each ferromagnets. From obtained results, it will be suggested that the measurements of the tunneling conductance in the junction provide us a useful information about the mechanism of itinerant ferromagnetism in metal.