Magnon and phonon assisted tunneling in a high-magnetoresistance tunnel junction using Co$_{75}$Fe$_{25}$ ferromagnetic electrodes

TL;DR

This paper investigates how magnon and phonon excitations influence tunneling in a high-magnetoresistance junction with CoFe electrodes, revealing two magnon branches and confirming theoretical models with experimental data.

Contribution

It demonstrates the combined role of magnon and phonon excitations in tunneling and identifies two magnon branches, advancing understanding of spin-dependent transport.

Findings

Magnon and phonon excitations both contribute to tunneling.

Two magnon branches with spins 1/2 and 3/2 are identified.

Theoretical models agree well with experimental results.

Abstract

Magnetoelectric properties of the spin-valve-type tunnel junction of Ta(5\ nm)/Ni$_{79}$Fe$_{21}$ (25 nm)/Ir$_{22}$Mn$_{78}$ (10 nm)/Co$_{75}$Fe$_{25}$ (4 nm)/Al (0.8 nm)-oxide/Co$_{75}$Fe$_{25}$ (4 nm)/Ni$_{79}$Fe$_{21}$ (20 nm)/Ta (5 nm) are investigated both experimentally and theoretically. It is shown that both magnon and phonon excitations contribute to the tunneling process. Moreover, we show that there are two branches of magnon with spin $S=1/2$ and 3/2 respectively. The theoretical results are in good agreement with the experimental data.