Influence of high-pressure heat treatment on magnetocaloric effects and magnetic phase transition in single crystal Gd3Ga5O12

The magnetic properties and magnetic phase transition critical behavior of Gd3Ga5O12single crystals subjected to high-pressure heat treatment were investigated. The results show that high-pressure heat treatment reduces the Curie temperature and magnetization of the sample. Under a magnetic field change of 5 T, the maximum isothermal magnetic entropy of the sample is approximately 19.73 J/(kg·K). High-pressure heat treatment increases the phase transition temperature range and leads to an increase in the magnetic refrigeration power. Both Gd3Ga5O12single crystals and the high-pressure heat-treated sample undergo a second-order phase transition. The critical behavior of the samples aligns with the mean field model acquired via critical model fitting. This indicates that the samples exhibit long-range exchange interactions in the system near the Curie temperature. Thus, this material can be used as a magnetic refrigerant for low-temperature applications.