Electric power transfer in spin pumping experiments

TL;DR

This paper introduces a new method to measure electric charge currents in spin pumping experiments using a closed circuit, providing insights into power dissipation and circuit modeling of spin pumping devices.

Contribution

It demonstrates the feasibility of charge current measurement via a closed circuit approach and models spin pumping cells as non-ideal voltage or current sources with internal resistance.

Findings

Charge currents can be measured with a closed circuit method.

Spin pumping cells can be modeled as non-ideal sources.

Power dissipation depends on load resistance.

Abstract

Spin pumping is becoming an established method to generate voltages from magnetic dynamics. The standard detection method of spin pumping is based on open circuit voltage measurement across ferromagnetic (FM) and non-magnetic (NM) bi-layers, where the inverse spin-Hall effect (ISHE) can convert spin currents into electrical charge accumulation. In this paper, we present that it is also possible to measure the associated electric charge current generated in FM/NM bi-layers, by using a macroscopic closed circuitry detection method. Using variable load resistors connected in series to the sample, we quantified charge currents and associated electric power dissipation as a function of the load resistance. By using basic circuit analysis, we are able to describe spin pumping cells as a non-ideal voltage source or equivalent current source with an internal resistor.