Single-crystal elastic and thermodynamic properties of γ-LiAlO2

The elastic properties of gamma- LiAlO 2 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 the literature, where c 12 and c 13 deviate from our results by up to 60% (46GPa). In contrast to the experimental c i j from the literature, we can recognize a good agreement between the elastic coefficients derived from RUS and the values using density functional theory. The dielectric permittivity was measured on large plane-parallel plates, and the piezoelectric stress coefficient e 123 = 0.14 C m - 2 was derived from RUS measurements at ambient conditions. The heat capacity between 4 and 398K has been obtained by microcalorimetry using a relaxation calorimeter. The Debye temperature was derived from heat capacity measurements ( Theta Cp = 676K) and RUS measurements ( Theta elastic = 688K).