A Magnetization Sensitive Potential at Garnet-Metal Interfaces

TL;DR

This study reveals a magnetization-dependent voltage at garnet-metal interfaces influenced by surface conditions, with observed variations and a proposed model, highlighting complex magnetic interactions not fully explained by bulk magnetoelectric effects.

Contribution

It introduces the observation of a magnetization-sensitive voltage at garnet-metal interfaces and proposes a simple model to explain the observed phenomena.

Findings

Voltage depends on surface roughness and pressure.

Significant variation between different metal surfaces.

Bulk magnetoelectric response is consistent with quadratic field terms.

Abstract

We investigate a magnetization-dependent voltage that appears at the interface between garnets and various metals. The voltage is even in the applied magnetic field and is dependent on the surface roughness and the pressure holding the surfaces together. Large variations in the size, sign and magnetic dependence are observed between different metal surfaces. Some patterns have been identified in the measured voltages and a simple model is described that can accommodate the gross features. The bulk magnetoelectric response of one of our polycrystalline YIG samples is measured and is found to be consistent with a term in the free energy that is quadratic in both the electric and magnetic fields. However, the presence of such a term does not fully explain the complex magnetization dependence of the measured voltages.