Investigation of Magnetocaloric Properties and Critical Behavior in Layered Type (Ce0.65La0.35)Mn2Ge2 Room Temperature Ferromagnet

The quaternary (Ce _0.65 La _0.35 )Mn ₂ Ge ₂ has been prepared by arc melting route from a low-cost misch metal (Ce _0.65 La _0.35 ) and its magnetic and magnetocaloric properties have been evaluated. (Ce _0.65 La _0.35 )Mn ₂ Ge ₂ belonging to body-centered tetragonal (BCT) structure of space group of I4/mmm exhibits a second-order transition from ferro to antiferromagnetic at 320 K. The field-dependent magnetization confirms the ferromagnetic nature below Curie temperature (320 K), showing the magnetization of 32 emu/g and the coercivity of 5.3 kOe at 10 K. The isothermal magnetic entropy change ( $\Delta S_{M}$ ) has been determined around transition temperature ( $T_{C}$ ) at various applied fields and the maximum $-\Delta S_{M}$ values are found to be 0.76–2.09 J/kg $\cdot \text{K}$ at an applied field of 10–50 kOe. The corresponding relative cooling power (RCP) values are 13–63 J/kg. The modified Arrott plots and field- and temperature-dependent magnetization in the vicinity of ferromagnetic-to-antiferromagnetic transition have been used to determine the critical behavior of (Ce _0.65 La _0.35 )Mn ₂ Ge ₂ . The values of the associated critical exponents $\delta $ , $\beta $ , and $\gamma $ are 4.77, 0.36, and 1.36, respectively, which are close to the values of 3-D Heisenberg theory indicating long-range magnetic interaction in (Ce _0.65 La _0.35 )Mn ₂ Ge ₂ compound.