Application of an external electric field of 1300 V/mm ∥ c induced the displacement of ∼3% of the chloride ions in the channels of a chlorapatite crystal with composition Ca10−x(PO4)6Cl2−2x□2x (x = 0.03). The percentage of the displaced ions corresponds to the concentration of the vacancies in the channels. The displacements bring about a partial reversal of the elementary dipoles in the ideally antiferroelectric structure and thus lead to a ferrielectric phase. At a field strength of 5000 V/mm chlorapatite became optically uniaxial and possibly ferroelectric.
Zeitschrift für Kristallographie – Crystalline Materials offers a place for researchers to present results of their crystallographic studies. The journal includes theoretical as well as experimental research. It publishes Original Papers, Letters and Review Articles in manifold areas of crystallography.