Internal friction evidence of intrinsic inhomogeneity in the paramagnetic region of La0.67Ca0.33MnO3

We have investigated the optimally doped manganite La0.67Ca0.33MnO3 by measurements of the resistivity ρ, magnetization M, Young's modulus E and internal friction Q−1. A remarkable peak in the Q−1 curve is observed in the paramagnetic (PM) region, and it is attributed to the formation of magnetic clusters. Furthermore, this peak is characteristic of thermally activated relaxation. Our observation is discussed combined with the analysis of the electrical transport and magnetic properties in PM region.