STUDY OF ANOMALIES NEAR 75°C IN LiNbO₃ BY X-RAY DIFFRACTION

The anomaly of LiNbO₃ in the vicinity of 75°C has been studied by various X-ray diffraction methods. An abrupt change of axial ratio (c/a) was measured, which may be ascribed to alternate rotation of NbO₆ octahedron about c axis. No change of structure symmetry was observed.