Anomaly in dilatation, linear birefringence and susceptibility of NiO at 400 K

Abstract Thermal expansion, linear birefringence, and ac susceptibility of NiO are measured between room temperature and the Neel point. All the measurements show a remarkably strong temperature dependence in the temperature range from 400 to 450 K. These anomalies are explained consistently by a change of the T-domain structure.