In Situ Ultraviolet Raman Study on the Phase Transition of Hafnia up to 2085 K

We have recently demonstrated that the Raman scattering through ultraviolet (UV) excitation is eminently well suited for in situ investigation of materials at high temperatures up to 1773 K. Here we report successful Raman measurements of HfO₂ up to 2085 K, using only a 100 mW power of UV laser line. The monoclinic-to-tetragonal transformation finished around 2080 K on heating, while the monoclinic phase appeared at 2018 K on cooling.