Thermodynamic properties of the CeSn3 mixed valence compound

Description

We have measured on the CeSn3 compound, the expansion coefficient between 80 and 800 K at normal pressure, the isothermal compressibility in the 0–8 GPa pressure range at room temperature and the heat capacity at constant pressure in the 60–300 K temperature range. The experimental data were compared with those previously found for the isomorphous LaSn3 phase, assumed as a proper reference material for the study of the intermediate valency states in CeSn3. Both the thermal expansion (3α) and the isothermal compressibility (k) of CeSn3 show behaviours quite different from those of LaSn3: for instance, in the standard conditions, 3α is 55 × 10−6K−1for CeSn3 and 38 × 10−6K−1for LaSn3; k is 15 × 10−12 Pa−1 and 12 × 10−12 Pa−1 respectively for CeSn3 and LaSn3. The thermal behaviour of the molar specific heat at constant pressure of CeSn3 is similar to that of LaSn3 for temperatures lower than 50 K. In the 70–300 K temperature range, the heat capacity of CeSn3 is clearly higher than that of LaSn3, ΔCp being maximum near 150 K. The analysis of the calorimetric data show that the electronic coefficient γ of CeSn3 is temperature dependent: its value varies from 53 mJ K−2 mole−1 at low temperature 24 mJ K−2 mole−1 at 300 K.

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