Elastic constants of praseodymium single crystals in the temperature range 4.2–300 K

Abstract

The elastic constants of single crystals of double hcp allotrope of praseodymium have been measured over the temperature range 4.2–300 K. Maxima are observed near 100 K in the temperature dependences of C11, C33, and (C11 − C12)/2, and minima are observed near 30 K. The maxima correlate with the upper temperature limit of an anomalous contribution which has been reported in the heat capacity. The minima correlate with peculiar behavior which has been observed in other physical phenomena. Inference may be drawn from the elasticity data that the thermal expansion behavior of praseodymium at low temperatures is very highly anisotropic. Comparison of the elastic constants of praseodymium with available data for the other rare earths shows that the praseodymium data fit a general pattern. Evaluation from the elastic constants shows that the Debye temperature of praseodymium remains nearly constant throughout the temperature range of measurement within ± 2 K of 152 K.