Ferromagnetic Semiconductor - Singlet (or Triplet) Superconductor - Ferromagnetic Semiconductor Systems as Possible Logic Circuits and Switches

TL;DR

This paper investigates how the critical temperature of thin superconducting films sandwiched between ferromagnetic insulators depends on magnetization orientations, proposing potential applications in logic circuits and switches, and exploring distinctions between singlet and triplet superconductors.

Contribution

It provides a theoretical analysis of the dependence of superconducting critical temperature on magnetization orientations in FI-S-FI systems for both singlet and triplet superconductors, suggesting new spintronic device concepts.

Findings

Critical temperature depends on relative magnetization orientation for singlet superconductors.

Critical temperature depends on absolute magnetization orientation for triplet superconductors.

Potential for using FI-S-FI systems as logic circuits and switches.

Abstract

We consider thin superconducting (S) films of thickness d $\ll \xi_{0}$, sandwiched between two ferromagnetic semiconducting insulators (FI) with differently orientated magnetizations - the FI-S-FI system. We calculate the dependence of the superconducting critical temperature on the orientation of the magnetization in the insulators and on the thickness of the superconducting film. The calculations are done for singlet as well as triplet superconductors. In the singlet case T_{c} depends on the relative orientation of the left and right magnetization only, while in the triplet case T_{c} depends on the absolute orientation of magnetization. The latter property can serve as a kind of spin-spectroscopy of triplet and unconventional superconductors, for instance in resolving the structure of the triplet order parameter in the recently discovered layered superconductor Sr_{2}RuO_{4}. The possibility of logic circuits and switches, which are based on the FI-S-FI systems with arbitrary orientation of magnetizations in FI films, is analyzed too.