Electric-power efficiency of anomalous Hall current

TL;DR

This study investigates the power dissipation and efficiency of anomalous Hall currents in a ferrimagnetic material, revealing a maximum efficiency at resistance matching and confirming theoretical predictions.

Contribution

It provides experimental insights into the power efficiency of anomalous Hall currents and validates recent theoretical models using a ferrimagnetic Hall bar.

Findings

Maximum power efficiency occurs at resistance matching.

Efficiency is proportional to the square of the anomalous-Hall angle.

Experimental results agree with non-equilibrium variational theory.

Abstract

The electric-power dissipation of the anomalous-Hall current injected into a lateral load circuit is studied. The anomalous-Hall current is generated by a $\mathrm{Co_{75}Gd_{25}}$ ferrimagnetic Hall bar and injected into lateral contacts lithographied at the two edges. The current, the voltage and the power injected in the lateral circuit are studied as a function of the magnetization state, the load resistance $R_l$, and the temperature. The power efficiency shows a sharp maximum as a function $R_l$, which corresponds to the condition of the resistance matching of the two sub-circuits. The maximum power efficiency is of the order of the square of anomalous-Hall angle. The observations are in agreement with recent predictions based on a non-equilibrium variational approach.