Large-tunneling anisotropic magneto-Seebeck effect in a CoPt/MgO/Pt tunnel junction

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 widths, reaching 175% at room temperature. This provides a sharp contrast to the magnetoresistance, in which CoPt/MgO/CoPt performs better by one order of magnitude for all barrier widths. Thus, by switching from two ferromagnetic layers to one (so that spin-orbit coupling alone governs the magnetic transport anisotropy), the magnetoresistance ratio diminishes while the magneto-Seebeck ratio remains comparable or improves considerably. We therefore demonstrate that magnetic tunability can increase when caused solely by spin-orbit coupling. This result sheds light on the role that spin-orbit coupling plays in magnetically tuning the properties of tunnel junctions