ZERO-FIELD MU+SR STUDY OF THE COLOSSAL MAGNETORESISTANCE MATERIAL LA0.67CA0.33MNO3

Zero-field mu(+)SR and resistivity experiments on La0.67Ca0.33MnO3 pow der show that the ferromagnetic transition temperature (T-C = 274 K) a nd resistivity peak temperature coincide to within 1 K, about 10 K hig her than T-C determined from the bulk magnetization. The sublattice ma gnetization nu(mu)(T) is well described for T less than or equal to T- C by (1 - T/T-C)(beta), where beta = 0.345 +/- 0.015. Unusual relaxati on dynamics suggest a wide distribution of Mn-ion correlation times. T hese results are discussed in terms of the effects of polarons on the spin and charge dynamics.