Competing effects at Pt/YIG interfaces: spin Hall magnetoresistance, magnon excitations and magnetic frustration

TL;DR

This study investigates how interface modifications in Pt/YIG devices influence spin Hall magnetoresistance and magnon transport, revealing surface magnetic frustration effects and their impact on spintronic device performance.

Contribution

It demonstrates that surface treatments can enhance spin-mixing conductance and magnon excitation efficiency, and uncovers the temperature-dependent magnetic frustration at YIG surfaces.

Findings

Surface treatment slightly increases spin-mixing conductance.

Efficiency of spin-to-magnon excitations is significantly enhanced.

Surface magnetic frustration causes sign change in SMR and suppresses MST at low temperatures.

Abstract

We study the spin Hall magnetoresistance (SMR) and the magnon spin transport (MST) in Pt/Y3Fe5O12(YIG)-based devices with intentionally modified interfaces. Our measurements show that the surface treatment of the YIG film results in a slight enhancement of the spin-mixing conductance and an extraordinary increase in the efficiency of the spin-to-magnon excitations at room temperature. The surface of the YIG film develops a surface magnetic frustration at low temperatures, causing a sign change of the SMR and a dramatic suppression of the MST. Our results evidence that SMR and MST could be used to explore magnetic properties of surfaces, including those with complex magnetic textures, and stress the critical importance of the non-magnetic/ferromagnetic interface properties in the performance of the resulting spintronic devices.