Spin-glass behavior and magnetocaloric properties of high-entropy perovskite oxides

The high-entropy concept has been recently proposed to be a promising paradigm to enhance the magnetocaloric properties of materials. Motivated by this, the magnetic properties and the magnetocaloric performance of two high-entropy perovskites (Dy1/4Ho1/4Er1/4Tb1/4)FeO3 and (Gd1/5Dy1/5Ho1/5Er1/5Tb1/5)FeO3 have been investigated. The magnetic measurements indicate that a spin-glass phase occurs at low temperatures in the high-entropy compounds, which is induced by the strong compositional disorder of rare-earth sublattice. The glassy state can lead to a sluggish magnetic transition and consequently a potential improvement in the magnetocaloric performance. Due to the increase in configurational entropy, large refrigerant capacity of 247 and 203 J/kg for a magnetic field change of 70 kOe is obtained in the (Gd1/5Dy1/5Ho1/5Er1/5Tb1/5)FeO3 and (Dy1/4Ho1/4Er1/4Tb1/4)FeO3 compounds, respectively. Our findings highlight the availability of spin order control through tuning the configurational entropy and demonstrate the key role of high-entropy design in enhancing the magnetocaloric properties of materials.