Density of states in the heterostructure ferromagnetic insulator-superconductor-ferromagnetic insulator

TL;DR

This paper investigates how the density of states in a superconductor sandwiched between ferromagnetic insulators varies with magnetic alignment, revealing insights into triplet superconductivity and spin-dependent effects.

Contribution

It introduces a numerical analysis of the DOS in FI-S-FI heterostructures using Usadel equations, highlighting the impact of magnetization misalignment on superconducting properties.

Findings

DOS varies with ferromagnet magnetization alignment

Zero bias peak formation linked to triplet components

Magnetization misalignment influences superconducting states

Abstract

We consider a spin valve composed of a superconducting film (S) between two ferromagnetic insulators (FI) on two sides. In the dirty limit the superconductor is described by Usadel equations. Appropriate boundary conditions were chosen for two S-FI interfaces, which are described via the interface parameter spin mixing angle. By numerically solving the Usadel equations, the density of states (DOS) at different spin mixing angles were obtained. It was shown previously that critical temperature of such FI-S-FI structure depends on the mutual alignment of the FI layers magnetization. We follow the evolution of DOS at change of misalignment of ferromagnets magnetization and probe the zero bias peak creation. The DOS characteristic features may give a fruitful information about triplet superconducting components creation and interplay inside the S layer.