Critical behavior near the ferromagnetic to paramagnetic phase transition temperature in polycrystalline La_(0.7)Ca_(0.2)Sr_(0.1)Mn_(1-x)Cr_xO_3 (x = 0.15 and 0.2)

摘要

The La_(0.7)Ca_(0.2)Sr_(0.1)Mn_(1-x)Cr_xO_3 (x = 0.15 and 0.20) samples have been prepared by solid-solid method. The crystallographic study shows that the samples crystallize in the orthorhombic system with Prima spacegroup. Investigations for temperature and magnetic-field dependences of magnetization indicated . gradual decrease of the ferromagnetic-paramagnetic transition temperature (Tc) from 234 to 224 K withincreasing Cr-doping. The experimental results reveal that all the samples undergo a second-order phase transition. The critical properties near ferromagnetic-paramagnetic phase transition temperature have been analyzed from data of static magnetization measurements for the samples, through various tech niques such as modified Arrott plot, Kouvel-Fisher method and critical isotherm analysis. The critical exponent values estimated from the isothermal magnetization measurements are found to be consistent and comparable to those values predicted by the short range 3D Ising model.