Adiabatic quantum pumping, magnification effects and quantum size effects of spin-torque in magnetic tunnel junctions

TL;DR

This paper investigates how adiabatic quantum pumping and quantum size effects influence spin-torque in magnetic tunnel junctions, revealing magnification effects and potential device advantages through a scattering matrix approach.

Contribution

It introduces a scattering matrix method to analyze quantum size and adiabatic pumping effects on spin-torque in magnetic tunnel junctions, highlighting magnification phenomena.

Findings

Quantum size effects depend on the normal metal layer thickness.

Magnification effects occur in spin-torque with ac voltages.

Spin-torque pumping offers advantages for device applications.

Abstract

We study the adiabatic quantum pumping and quantum size effects of spin-torque in a magnetic tunnel junction within a scattering matrix approach. Quantum size effects are predicted in the presence of a dc bias as a function of the thickness of the normal metal layer inserted between two magnetic layers and of the fixed magnetic layer. In the presence of ac voltages, the results for the spin-torque show a peculiar magnification effect and advantages of spin-torque pumping in actual devices are also discussed.