α-Pb 3(PO 4) 2 — A pure ferroelastic

Abstract

Single crystals of Pb 3(PO 4) 2 were grown by the Czochralski technique. Transparent oriented crystal sections exhibit a pattern of ferroelastic domains which are readily movable with applied external stress. The high-temperature parent phase, β-Pb 3(PO 4) 2, transforms to the α modification at 180°C. _This transformation corresponds to the Aizu (1) species, 3mF2/m, which supports full ferroelasticity. The predicted number of domain walls have been observed.