Thermal expansion anomalies of samarium monosulfide in the temperature range of 150-240 K

The temperature coefficient of monocrystalline SmS linear expansion (α) from 90 to 300 K range was mwasured. Betweeen 150 and 240 K numerical values and the form of the function α(t) depend on the rate of sample cooling (Vcool). Two anomalies were found on the dependence α(T) near T=185 K and in the range 190-240 K) when Vcool=0,2 K/mnin. It is assumed that these anomalies are due to the ordering of the structural vacancies, which is expected to take place in high Tc superconductors