Simultaneous measurement of specific heat, thermal conductivity, and thermal diffusivity of modified barium titanate ceramics

A radiation calorimeter makes it possible to measure the specific heat, thermal conductivity, and thermal diffusivity of a solid sample simultaneously and independently. Because the three thermal quantities are not independent each other, a self-check of the reliability of the obtained values can also be made from results. Measurements were performed for ferroelectric BaTiO3 ceramics modified with a small amount of Zr, Sn, and Hf in the temperature range of 300–450 K. The modifier content was changed from 2.5 to 12 mol% of Ti ion. Results indicate that the temperature dependence of thermal conductivity changes from crystalline-like to amorphous-like with an increase of content.