Large magnetic entropy change and prediction of magnetoresistance using a magnetic field in LaSmSrMnInO.

A detailed study of the structural, magnetic, magnetocaloric and electrical effect properties in polycrystalline manganite LaSmSrMnInO is presented. The X-ray diffraction pattern is consistent with a rhombohedral structure with 3̄ space group. Experimental results revealed that our compound prepared a sol-gel method exhibits a continuous (second-order) ferromagnetic (FM) to paramagnetic (PM) phase transition around the Curie temperature ( = 300 K). In addition, the magnetic entropy change was found to reach 5.25 J kg K under an applied magnetic field of 5 T, corresponding to a relative cooling power (RCP) of 236 J kg. We have fitted the experimental data of resistivity using a typical numerical method (Gauss function). The simulation values such as maximum resistivity ( ) and metal-semiconductor transition temperature ( ), calculated from this function, showed a perfect agreement with the experimental data. The shifts of these parameters as a function of magnetic field for our sample have been interpreted. The obtained values of and , determined by analyzing the Arrott plots, are found to be = 298.66 ± 0.64 K, = 0.325 ± 0.001 and = 1.25 ± 0.01. The critical isotherm ( , ) gives = 4.81 ± 0.01. These critical exponent values are found to be consistent and comparable to those predicted by the three-dimensional Ising model with short-range interaction. Thus, the Widom scaling law is fulfilled.