The sound velocity, internal friction, and thermal expansion in a single crystal of La0.85Sr0.15MnO3

The results are given of the investigation of the temperature dependence of the sound velocity v, internal friction Q(-1), and thermal expansion Delta L/L of a single crystal of La0.85Sr0.15MnO3 in the temperature range from 5 to 400 K. Clearly defined singularities of the elastic properties at a tem perature of charge ordering T-co approximate to 200 K are revealed. The res ults of X-ray diffraction studies performed at room temperature are used to determine the orientations and estimate the sizes of twins. The correlatio n between magnetic and structure inhomogeneities is established. Based on t he results of analysis of the temperature dependence of internal friction a nd thermal expansion, an assumption is made of the presence in a single cry stal of La0.85Sr0.15MnO3 of a structural transition in the temperature rang e from 15 to 60 K that has not been observed previously. (C) 2001 MAIK "Nau ka/ Interperiodica".