Enhancing the thermal conductivity of EuTiO3-based magnetocaloric materials by constructing continuous Cu networks

EuTiO 3 -based materials (ETO) exhibit impressive magnetocaloric performance, but the low thermal conductivity restricts their practical applications. Therefore, enhancing the thermal conductivity of these materials is crucial to advance their applications in magnetic refrigeration technology. Herein, we present a novel approach to enhance the thermal conductivity of EuTiO 3 -based magnetocaloric materials by constructing continuous Cu networks. For this purpose, copper plating layers were deposited on the surface of EuTi 0.75 Al 0.125 Zr 0.125 O 3 (ETAZO) powders via electroless plating. The influences of plating temperature, pH value, and plating duration on the structure and morphology of the plated copper layer were investigated, obtaining the optimal process for electroless copper plating on ETAZO microspheres. The formation process of copper plating layers was investigated, revealing the mechanism of electroless copper plating. On this basis, continuous Cu networks were successfully constructed in a cold-pressed ETAZO/Cu composite. The high thermal conductivity of copper enables rapid heat conduction through Cu networks, thereby significantly enhancing the thermal conductivity of the composite. Encouragingly, the thermal conductivity of the composite reaches 2.18 W m −1 K −1 at 4.2 K, indicating an increase of 35 times compared to ETAZO (0.06 W m −1 K −1 ). Meanwhile, the maximum magnetic entropy change of the composite under the magnetic field change of 0‒1 T remains 15.6 J kg −1 K −1 , exhibiting impressive magnetocaloric performance. The combination of outstanding magnetocaloric effect and high thermal conductivity enables ETAZO/Cu composite to be a practical cryogenic magnetic refrigerant.