Thermal Diffusivity and Phase Transition of Rare Earth Manganites

Abstract

Thermal diffusivity of nonstoichiometric PrMnO3 and NdMnO3 phases were measured by laser flash method from room temperature to 1100 K, in addition to the data of electrical conductivity, thermal analysis and high temperature X-ray diffractometry to detect the phase transition. The thermal diffusivity curve varied with increasing temperature and showed a clear anomaly with a sudden dip at the phase transition temperature. The transition temperature decreases with oxygen nonstoichiometry in each phase.

Fabrication of dense yttrium oxyfluoride ceramics by hot pressing and their mechanical, thermal, and electrical properties

“…It is believed that these changes are caused by the phase transition of YOF between rhombohedral and tetragonal at around 600 °C. [40][41][42][43] Thus, thermal properties of the YOF ceramics were unstable. It is difficult to fabricate complexshape and large size devices, such as plasma proof dome, vacuum chuck, and end effecter, by a conventional sintering process owing to the thermal instability of YOF.…”