Above-room-temperature giant thermal conductivity switching in spintronic multilayer

TL;DR

This paper demonstrates a giant, room-temperature magnetic-field-induced modulation of thermal conductivity in a spintronic multilayer, highlighting its potential for nanoscale thermal management and switching applications.

Contribution

It reports the first observation of a giant magneto-thermal resistance effect in a Cu/CoFe multilayer at room temperature, with a ratio of 150%, surpassing previous records.

Findings

Magneto-thermal resistance ratio reaches 150% at room temperature.

The effect persists with ~100% ratio up to 400 K.

Thermal conductivity modulation exceeds electrical conductivity changes.

Abstract

Thermal switching provides an effective way for active heat flow control, which has recently attracted increasing attention in terms of nanoscale thermal management technologies. In magnetic and spintronic materials, the thermal conductivity depends on the magnetization configuration: this is the magneto-thermal resistance effect. Here we show that an epitaxial Cu/Co$_{50}$Fe$_{50}$ multilayer film exhibits giant magnetic-field-induced modulation of the cross-plane thermal conductivity. The magneto-thermal resistance ratio for the Cu/Co$_{50}$Fe$_{50}$ multilayer reaches 150% at room temperature, which is much larger than the previous record high. Although the ratio decreases with increasing the temperature, the giant magneto-thermal resistance effect of ~100% still appears up to 400 K. The magnetic field dependence of the thermal conductivity of the Cu/Co$_{50}$Fe$_{50}$ multilayer was observed to be about twice greater than that of the cross-plane electrical conductivity. The observation of the giant magneto-thermal resistance effect clarifies a potential of spintronic multilayers as thermal switching devices.