Birefringence of SrTiO₃at the ferroelastic phase transition

Abstract

A birefringence-imaging study of a crystal of SrTiO3 shows a purely second-order phase transition close to 105 K with no measurable indications of critical fluctuations. The near perfectly linear development of the birefringence near the phase transition is consistent with normal Landau mean-field behaviour with an order-parameter critical exponent close to 0.5.