Single-crystal elastic and thermodynamic properties of gamma-LiAlO2

Abstract

ABSTRACT: The elastic properties of γ-LiAlO2 were reinvestigated with the aid of resonant ultrasound spectroscopy (RUS) at ambient conditions. A strong discrepancy of the elastic coefficients derived by RUS can be found from the experimental results from literature, where c12 and c13 deviate from our results by about 15 % (24 GPa) and 60 % (42 GPa), respectively. In contrast to the experimental cij from literature we can recognize a good agreement between the elastic coefficients derived from RUS and the values using density functional theory (DFT). The dielectric permittivity was measured on large plane-parellel plates and the piezoelectric stress coefficient e123 = 0.14 C m−2 was derived from RUS measurements at ambient conditions. The heat capacity between 4 K – 398 K has been obtained by microcalorimetry using a relaxation calorimeter. The Debye temperature was derived from heat capacity measurements (⊝ Cp = 676 K) and from RUS measurements (⊝ elastic = 688 K).