PYROELECTRIC PROPERTIES OF BETA-BAB2O4 IN THE TEMPERATURE-RANGE FROM 2.5 TO 90 K

Results are presented of experimental studies of how the spontaneous p olarization of beta-BaB2O4 (BBO) varies with temperature in the range from 2.5 to 90 K. Values of the pyroelectric coefficient gamma(s) are calculated, and effective values of the Debye temperature (Theta = 112 K) and the Einstein temperature (Theta(E) = 28 K) are estimated. It i s shown that the dominant contribution to gamma(s) comes from acoustic lattice modes. A mechanism is proposed to explain why the temperature dependence of the pyroelectric effect in linear pyroelectric material s is different from that in ferroelectrics. (C) 1997 American Institut e of Physics.