CRITICAL PHENOMENA IN THE DOUBLE-EXCHANGE FERROMAGNET LA0.7SR0.3MNO3

We report a dt magnetization study of the critical phenomena in a high -quality single crystal of the double-exchange ferromagnet La0.7Sr0.3M nO3. We have determined the critical temperature (T-C = 354.0 +/- 0.2 K) and the critical exponents, beta = 0.37 +/- 0.04 and gamma - 1.22 /- 0.03. Here beta and gamma are the critical exponents for the temper ature dependence of the spontaneous magnetization just below T-C and i nitial susceptibility just above Tc. Using these values of beta, gamma , and T-C, we find that the magnetization-field-temperature (M-H-T) be havior below and above Te obeys scaling, following a single equation o f state in which M/(1 - T/T-C)(beta) is uniquely related to M/(1 - T/T -C)(beta) [S0031-9007(98)07738-2].