Premium
Size driven thermodynamic crossovers in phase stability in zirconia and hafnia
Author(s) -
Sharma Geetu,
Ushakov Sergey V.,
Navrotsky Alexandra
Publication year - 2018
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.15200
Subject(s) - hafnia , monoclinic crystal system , cubic zirconia , tetragonal crystal system , enthalpy , materials science , amorphous solid , surface energy , phase (matter) , chemical stability , cristobalite , thermodynamics , crystallography , crystal structure , chemistry , ceramic , metallurgy , composite material , physics , quartz , organic chemistry
Hafnia (HfO 2 ) and zirconia (ZrO 2 ) are of great interest in the quest for replacing silicon oxide in semiconductor field effect transistors because of their high permittivity. Both exhibit extensive polymorphism and understanding the energetics of their transitions is of major fundamental and practical importance. In this study, we present a systematic thermodynamic summary of the influence of particle size on thermodynamic phase stability in hafnia and zirconia using recently measured enthalpy data from the literature. The amorphous phase is found to be the most energetically stable above 165 and 363 m 2 /g of surface area for HfO 2 and ZrO 2 , respectively. Below 16 and 20.3 m 2 /g of surface area, respectively, the monoclinic phase is the most energetically stable for HfO 2 and ZrO 2 . At intermediate sizes there are closely balanced energetics among monoclinic, tetragonal, and cubic phases. The energy crossovers reflect decreasing surface enthalpy in the order monoclinic, tetragonal, cubic and amorphous for both hafnia and zirconia.