Temperature evolution of the ferroelastic order parameter of Li₂TiGeO₅

Abstract

The temperature dependence of the order parameter of Li₂TiGeO₅ ferroelastic was determined on the basis of several independent measurements: specific heat, birefringence and IR spectroscopy. The estimated temperature evolution of order parameter is in very good agreement with mean field Landau theory in temperature range 40 < T < 233.5 K. The character of the above mentioned dependence unequivocally confirms the second-order phase transition in Li₂TiGeO₅ at 233.5 K.

Keywords:

• ferroelastic
• order parameter
• phase transition
• Landau theory

Acknowledgements

The author would like to thank R. Poprawski for providing useful technical assistance and fruitful discussions.