Gate control of the tunneling magnetoresistance in double-barrier junctions

TL;DR

This paper demonstrates that applying a gate voltage to a double magnetic tunnel junction can significantly enhance and control the tunneling magnetoresistance by tuning quantum well states, offering a new approach for spintronic device design.

Contribution

It introduces a method to control TMR in double magnetic tunnel junctions using gate voltage, providing a more effective alternative to changing layer thickness.

Findings

Gate voltage strongly affects TMR via quantum well state tuning.

Significant TMR enhancement achievable through gate control.

Potential application in future spintronic devices.

Abstract

We calculate the conductances and the tunneling magnetoresistance (TMR) of double magnetic tunnel junctions, taking as a model example junctions composed of Fe/ZnSe/Fe/ZnSe/Fe (001). The calculations are done as a function of the gate voltage applied to the in-between Fe layer slab. We find that the application of a gate voltage to the in-between Fe slab strongly affects the junctions' TMR due to the tuning or untuning of conductance resonances mediated by quantum well states. The gate voltage allows a significant enhancement of the TMR, in a more controllable way than by changing the thickness of the in-between Fe slab. This effect may be useful in the design of future spintronic devices based on the TMR effect, requiring large and controllable TMR values.