Texture-irrelevant thermal conductivity and expansion properties of La2Ce2O7 ceramics

Abstract

Cubic crystals are generally known to be isotropic with respect to second rank property tensor and hence expected to show no change in relation to the measurements involving such properties. In a stark contrast, fluorite (Fm3¯m) cubic textured La2Ce2O7 ceramic depicted a strong dependence with electrical resistivity in our recent study. This motivated us to examine the effect of texture on other second rank tensor properties, namely, thermal conductivity (TC) and thermal expansion coefficient (TEC). The texturing in La2Ce2O7 ceramic took place along the closest packed 〈111〉 direction. The thermophysical properties (TC and TEC), measured for both textured and un-textured ceramics, depicted no special relevance of texture; reveling a fundamental difference between electron conduction and thermal conduction via phonons. The dependence of thermophysical properties on the cubic systems seems to extend beyond symmetry; a number of such factors are highlighted.