Effect of high-energy ball milling on the phase transition of Sn2P2S6 ferroelectric crystals

The Sn 2 P 2 S 6 ferroelectric nanocrystalline powders have been prepared by high-energy milling and their size distribution has been determined. The temperature dependences of heat capacity and the temperatures of phase transitions of ferroelectric nanopowders are obtained. The modified model of B. Jiang and L. Bursill [Phys. Rev. B 60 , 9978 (1999)] for the ferroelectric nanoparticles with phase transitions close to the tricritical Lifshitz point is proposed and used to explain the experimental results. Observed smearing of the heat capacity anomaly is explained by the particle size effect and the influence of defects. The influence of the milling time on the investigated properties of Sn 2 P 2 S 6 ferroelectric powders was studied.