ANOMALOUS 2ND-HARMONIC GENERATION IN IRON-DOPED BARIUM-TITANATE

The temperature evolution of the angular dependence of the second harm onic intensity in iron-doped barium titanate is measured in the region of the transition from the cubic to the tetragonal phase. An unusual asymmetry of the angular distribution of this intensity is found in th e temperature range corresponding to the peak in the temperature depen dence of the integral intensity. The possible physical mechanisms of t hese anomalies are discussed. (C) 1996 American Institute of Physics.