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

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 magnetothermal resistance effect. Here, we show that an epitaxial Cu/Co50Fe50 multilayer film exhibits giant magnetic-field-induced modulation of the cross-plane thermal conductivity. The magnetothermal resistance ratio for the Cu/Co50Fe50 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 magnetothermal resistance effect of similar to 100% still appears up to 400K. The magnetic field dependence of the thermal conductivity of the Cu/Co50Fe50 multilayer was observed to be about twice greater than that of the cross-plane electrical conductivity. The observation of the giant magnetothermal resistance effect clarifies the potential of spintronic multilayers as thermal switching devices.