Oscillations of the Critical Temperature in a (Fe/Cr/Fe)/V/Fe Heterostructure

TL;DR

This study investigates how the superconducting transition temperature oscillates in a layered Fe/Cr/Fe/V/Fe heterostructure, revealing nonmonotonic behavior linked to magnetic structure variations as Cr layer thickness changes.

Contribution

It provides experimental and theoretical analysis of $T_c$ oscillations in a layered heterostructure, connecting magnetic states to superconducting properties through a proximity effect model.

Findings

Critical temperature $T_c$ oscillates nonmonotonically with Cr layer thickness.

Magnetic states, including small domain structures, influence $T_c$ behavior.

Proximity effect theory explains the relationship between magnetic structure and $T_c$ oscillations.

Abstract

The superconducting and magnetic properties of the (Fe/Cr/Fe)/V/Fe layered system with variable thickness of the chromium layer have been experimentally and theoretically studied. The magnetic properties of the system have been studied by the ferromagnetic resonance method, and the superconducting transition temperature has been measured from the jump in the magnetic susceptibility. A wide variety of magnetic states are observed in the system; in particular, the structure of small domains can arise in the iron layer placed between vanadium and chromium. It has been shown experimentally that the critical temperature $T_c$ of the superconducting transition undergoes nonmonotonic oscillations with a noticeable amplitude in the given system with the change in the thickness of the Cr layer. The proposed model based on the proximity effect theory makes it possible to relate these $T_c$ oscillations to the features of the magnetic structure of the samples.