Coexistence of tunneling magnetoresistance and Josephson effects in SFIFS junctions

O Vávra,Ch Strunk,J Fabian,N Himmel,I Vávra,A Petraru,R Soni,H Kohlstedt

doi:10.1063/1.4976822

Abstract

We demonstrate an integration of tunneling magnetoresistance and the Josephson effects within one tunneling junction. Several sets of Nb-Fe-Al-Al2O3-Fe-Nb wafers with varying Al and Fe layers thickness were prepared to systematically explore the competition of TMR and Josephson effects. A coexistence of the critical current IC(dFe) and the tunneling magnetoresistance ratio T M R(dFe) is observed for iron layer dFe thickness range 1.9 and 2.9 nm. Further optimization such as thinner Al2O3 layer leads to an enhancement of the critical current and thus to an extension of the coexistence regime up to dFe≃3.9 nm Fe.

Highlights

Singlet superconductivity is based upon the formation of electron pairs with opposite spins and momenta, whereas the magnetization of ferromagnets is based on spontaneous parallel spin alignment
Josephson junctions with embedded pseudospin valves reveal that the Josephson coupling can be controlled in both magnitude[9,10] and phase.[11]
Initial experiments on Josephson junctions with spin valves as weak links based on the tunneling magnetoresistance (TMR) were made based on Nb and Ni.[12]

Summary

Introduction

Singlet superconductivity is based upon the formation of electron pairs with opposite spins and momenta, whereas the magnetization of ferromagnets is based on spontaneous parallel spin alignment. Coexistence of tunneling magnetoresistance and Josephson effects in SFIFS junctions

Results

Conclusion