Enthalpy and Volume Changes for m-t Phase Transition in HfO2

Objective
HfO2 is a prospective material for application as high-temperature ceramic and (transformation toughening above 1100OC) high-K dielectric in integrated circuits (reducing leakage current compared with SiO. HfO2 isostructural to zirconium oxide and undergo monoclinic-tetragonal and tetragonal-cubic translations with temperate.
High Temperature phases are not quenchable but can be obtained in high area samples. Monoclinic-tetragonal transition in hafnia is critical for its application. However, there are no thermochemical data on phase transitions in HfO2 The objective of this works was to determine enthalpy and volume changes for m-t transition in HfO2 by direct measurements.