Temperature dependence of the lattice parameters and the thermal expansion of CdCr 2X 4 (X ≡ S, Se)

Abstract

A precise X-ray determination of the lattice parameters of the ferro-magnetic chromium chalcogenide spinel compounds CdCr 2S 4 and CdCr 2Se 4 was made in the temperature range 28–685 °C using a Unicam 19 cm high temperature powder camera. These data were used to evaluate the coefficients of thermal expansion at various temperatures by a graphical method. The coefficient of thermal expansion increases non-linearly with increasing temperature in both the compounds. The thermal expansion behaviour of these compounds is discussed in relation to their structure and other physical properties.