Influence of high-pressure heat treatment on magnetic property and phase transition critical behavior in La0.75Sr0.25Mn1- xCoxO3 (x = 0, 0.1, 0.2)

In this study, La0.75Sr0.25Mn1-xCoxO3 (x = 0, 0.1, 0.2) samples were synthesized using a high-pressure heat treatment method, and their magnetic properties and critical phase transition behaviors were systematically investigated. The prepared samples exhibited excellent single-phase characteristics with space group R 3 c. As the Co content increased, TC decreased from 325 to 211 K. In a 7 T magnetic field, the RCP values of the samples increased from 364.52 to 384.66 J & sdot;kg- 1, significantly enhancing the cooling efficiency of the samples. The three samples exhibited a second-order phase transition, indicating a relatively small hysteresis in the system. The critical exponents were obtained by MAPs and K-F method. These results indicate that with an increase in Co doping, the beta values also increase, suggesting that Co doping facilitates the establishment of long-range ferromagnetic order in the three samples.