Pyroelectric properties of ReCOB and BiBO oxyborate crystals with monoclinic symmetry

Abstract

Pyroelectric properties of oxyborate crystals with monoclinic structure, including ReCa 4 O(BO 3 ) 3 (ReCOB, Re: rare-earth elements) and BiB 3 O 6 (BiBO), were investigated by charge integration method. The pyroelectric p 1 of ReCOB crystals was found to be negative, being on the order of -59.3~-65.5 C/(m 2 · o C) at 30 o C, while the pyroelectric p 3 was determined to be positive, being around 11.6~31.0 C/(m 2 · o C). The pyroelectric coefficients p 1 and p 3 for ReCOB crystals were observed to decrease with increasing temperature, with variations being on the order of -10.8% to -79.1% over the test temperature range of 20~180 o C. Comparing with ReCOB crystals, larger pyroelectric coefficient (p 2 ) was obtained for BiBO crystals, being on the order of 105.0 C/(m 2 · o C) at room temperature, maintaining the similar value up to 180 o C. Of particular interest is that ReCOB and BiBO crystals were found to possess relative high detectivity F d , two to three times that of commercial TGS and LiTaO 3 .