Effect of Joule heating in current-driven domain wall motion

TL;DR

This study investigates how Joule heating affects current-driven domain wall motion in Ni81Fe19 wires, revealing that high current densities significantly raise sample temperature, potentially surpassing the Curie point and altering magnetic structures.

Contribution

It provides quantitative analysis of Joule heating effects during domain wall motion, linking high current densities to temperature rise and magnetic phase changes.

Findings

Sample temperature reached 750 K at threshold current density.

Temperature approached 830 K near the Curie temperature.

Multi-domain structures appeared when exceeding critical current density.

Abstract

It was found that high current density needed for the current-driven domain wall motion results in the Joule heating of the sample. The sample temperature, when the current-driven domain wall motion occurred, was estimated by measuring the sample resistance during the application of a pulsed-current. The sample temperature was 750 K for the threshold current density of 6.7 x 10^11 A/m2 in a 10 nm-thick Ni81Fe19 wire with a width of 240 nm. The temperature was raised to 830 K for the current density of 7.5 x 10^11 A/m2, which is very close to the Curie temperature of bulk Ni81Fe19. When the current density exceeded 7.5 x 10^11 A/m2, an appearance of a multi-domain structure in the wire was observed by magnetic force microscopy, suggesting that the sample temperature exceeded the Curie temperature.