Large Tunneling Anisotropic Magneto-Seebeck Effect in a CoPt|MgO|Pt Tunnel Junction

TL;DR

This paper theoretically demonstrates a large tunneling anisotropic magneto-Seebeck effect in CoPt|MgO|Pt tunnel junctions, showing significant thermal magnetic-transport anisotropy that surpasses the effect in similar structures and differs fundamentally from magnetoresistance.

Contribution

The study reveals a significantly larger magneto-Seebeck ratio in CoPt|MgO|Pt compared to CoPt|MgO|CoPt, highlighting a new thermal magnetic-transport phenomenon with potential applications.

Findings

Magneto-Seebeck ratio exceeds 175% at room temperature for small barrier thicknesses.

Magneto-Seebeck effect and magnetoresistance have opposite behaviors and different origins.

CoPt|MgO|Pt exhibits strong thermal magnetic-transport anisotropy.

Abstract

We theoretically investigate the Tunneling Anisotropic Magneto-Seebeck effect in a realistically-modeled CoPt|MgO|Pt tunnel junction using coherent transport calculations. For comparison we study the tunneling magneto-Seebeck effect in CoPt|MgO|CoPt as well. We find that the magneto-Seebeck ratio of CoPt|MgO|Pt exceeds that of CoPt|MgO|CoPt for small barrier thicknesses, reaching 175% at room temperature. This result provides a sharp contrast to the magnetoresistance, which behaves oppositely for all barrier thicknesses and differs by one order of magnitude between devices. Here the magnetoresistance results from differences in transmission brought upon by changing the tunnel junction's magnetization configuration. The magneto-Seebeck effect results from variations in asymmetry of the energy-dependent transmission instead. We report that this difference in origin allows for CoPt|MgO|Pt to possess strong thermal magnetic-transport anisotropy.