# Long-range triplet proximity effect in multiply connected ferromagnet-superconductor hybrids

## TL;DR

This paper investigates how long-range spin-triplet correlations affect the switching of vorticity states and the critical temperature in mesoscopic superconductor/ferromagnet hybrids, using the linearized Usadel equations.

## Contribution

It introduces a theoretical analysis of the interplay between exchange fields, Little--Parks oscillations, and spin-triplet correlations in S/F hybrid structures.

## Key findings

- Exchange field induces vorticity switching in superconducting states.
- Long-range triplet correlations influence the critical temperature oscillations.
- Superconducting Tc can be increased by magnetic field due to vorticity switching.

## Abstract

Applying the linearized Usadel equations, we consider the nucleation of superconductivity in multiply connected mesoscopic superconductor/ferromagnet (S/F) hybrids such as a thin superconducting ring on a ferromagnet with a uniform in-plane magnetization M and a spin-active S/F interface. We demonstrate that the exchange field in F provokes a switching between superconducting states with different vorticities which may increase the critical temperature ( Tc ) of the superconductor in a magnetic field. We study the interplay between oscillations in Tc due to the Little--Parks effect and oscillations in Tc induced by the exchange field. Furthermore, we analyse the influence of long-range spin-triplet correlations on the switching between different vorticities.