We report a dc magnetization study of the critical phenomena in a high-quality single crystal of the double-exchange ferromagnet ${\mathrm{La}}_{0.7}{\mathrm{Sr}}_{0.3}{\mathrm{MnO}}_3$. We have determined the critical temperature $(T_C=354.0\mathrm{}\pm 0.2\mathrm{K})$ and the critical exponents, $\beta =0.37\mathrm{}\pm 0.04$ and $\gamma =1.22\mathrm{}\pm 0.03$. Here $\beta$ and $\gamma$ are the critical exponents for the temperature dependence of the spontaneous magnetization just below $T_C$ and initial susceptibility just above $T_C$. Using these values of $\beta$, $\gamma$, and $T_C$, we find that the magnetization-field-temperature $\left(M-H-T\right)$ behavior below and above $T_C$ obeys scaling, following a single equation of state in which $M/({1-T/T}_C{)}^{\beta }$ is uniquely related to $H/({1-T/T}_C{)}^{\beta +\gamma }$.

• Received 17 February 1998

DOI:https://doi.org/10.1103/PhysRevLett.81.4740