Critical behavior in single-crystalline La_0.67Sr_0.33CoO₃

Abstract

The critical behavior of La_0.67Sr_0.33CoO₃ single crystal has been investigated from the bulk magnetization measurements around the Curie temperature (T C). The detailed analysis of the magnetization indicates the occurrence of a continuous ferromagnetic to paramagnetic phase transition at 223.0 K. The critical exponents β= 0.361±0.007, γ= 1.31±0.001, and δ= 4.64±0.01 characterizing this second order phase transition, have been estimated using different techniques such as the Kouvel-Fisher plot, the Arrott-Noaks plot, and critical isotherm analysis. With these values of T C, β, and γ, one can scale the magnetization below and above T C following a single equation of state. The consistency in the values of the critical exponents obtained from different methods and the well-obeyed scaling behavior confirm that the calculated exponents are unambiguous and purely intrinsic to the system. These values of the exponents match well with those theoretically predicted for the three-dimensional Heisenberg model with nearest-neighbor interaction.