Critical Behavior Near the Ferromagnetic Transition in Phase-Separated $$\hbox {La}_{0.5}\hbox {Ca}_{0.2}\hbox {Sr}_{0.3}\hbox {MnO}_{3}$$ La 0.5 Ca 0.2 Sr 0.3 MnO 3 Manganite

Abstract

The critical behavior of $$\hbox {La}_{0.5}\hbox {Ca}_{0.2}\hbox {Sr}_{0.3}\hbox {MnO}_{3}$$ manganite has been investigated by measuring the magnetization around the Curie temperature $$T_\mathrm{C}$$ . The experimental results indicate that this sample exhibits a second-order phase transition. The critical exponents ( $$\beta $$ , $$\gamma $$ and $$\delta $$ ) are estimated using the Kouvel–Fisher technique and critical isotherm analysis. The reliability of obtained exponents was confirmed by using the universal scaling hypothesis. The obtained $$\beta $$ value ( $$=0.47$$ ) is close to that expected for the mean-field model ( $$=0.5$$ ), while the $$\gamma $$ value ( $$=1.28$$ ) lies between the 3D Ising ( $$=1.24$$ ) and 3D Heisenberg ( $$=1.336$$ ) models. This reveals that the critical exponents of this half-doped manganite do not correspond to the conventional universality classes. In addition, the results show that the ferromagnetic interaction is of itinerant type.