Magnetic Properties of ${\mathrm{La}}_{0.5}$${\mathrm{Sr}}_{0.5}$Co${\mathrm{O}}_3$ near Its Curie Temperature

Samples of ${\mathrm{La}}_{0.5}$ ${\mathrm{Sr}}_{0.5}$Co${\mathrm{O}}_3$ were prepared, and a study was made of their electrical and magnetic properties. Investigation of the initial susceptibility immediately above the Curie point $T_c$ determined that the critical exponent $\gamma =1.27\mathrm{}\pm 0.02$, where $\gamma$ is defined by the equation ${{\chi }_0}^{-1\mathrm{}}=A(T-T_c)\gamma$. In addition, we found that $\delta =3.05\mathrm{}\pm 0.06$ at $T=T_c$, where the magnetic moment $\sigma$ and the magnetic field $H_i$ are related by the equation $H_i=A^{\prime }{\sigma }^{\delta }$. The difference between these results and those previously reported for other ferromagnetic materials is discussed. However, despite this difference, the interrelationship of magnetic field, magnetic moment, and temperature is found to obey the magnetic equation of state recently proposed by Kouvel and Rodbell.