Pyroelectric properties of high-resistivity rubidium titanyl phosphate crystals in the 4.2-300 K temperature range

摘要

Pyroelectric properties of high resistivity RbTiOPO_4 single crystals cut from different growth sectors ({100}, {110} and {201}) have been studied using the modified static method in a broad temperature interval, from 4.2 to 300 K. A substantial scatter of the room temperature pyroelectric coefficient values has been observed, ranging from 1.3 to 4.6 10~(-5) C/m~2 K, for samples of distinct stoichiometry. Different types of low-temperature anomalies in the pyroelectric coefficient behavior have been revealed in samples related to the various growth sectors. Crystals cut from the {110} sector exhibit particularly interesting anomalies at 90 and 250 K which are attributed to oxygen deficient PO_4(1) and PO_4(2) coordinational tetrahedral and their relaxor contribution. This and other anomalies are discussed in terms of the growth related variation of the RTP crystals' nonstoichiometry and point defect structure.