Zero-field μ+SR study of the colossal magnetoresistance material La0.67Ca0.33MnO3

Zero-field μ⁺SR and resistivity experiments on La0.67Ca0.33MnO3 powder show that the ferromagnetic transition temperature (TC = 274 K) and resistivity peak temperature coincide to within 1 K, about 10 K higher than TC determined from the bulk magnetization. The sublattice magnetization vμ(T) is well described for T ≤ TC by (1 - T/TC)^β, where β = 0.345 ± 0.015. Unusual relaxation dynamics suggest a wide distribution of Mn-ion correlation times. These results are discussed in terms of the effects of polarons on the spin and charge dynamics.