Specific features of the pyroelectric properties of actual RbTiOPO4 single crystals in the temperature range 4.2-300 K

摘要

The pyroelectric properties of samples cut from various growth sectors of RbTiOPO4 single crystals grown from solution in a melt were measured in the temperature range from 4.2 to 300 K. The experimental values of the pyroelectric coefficient range from -1.3 x 10(-5) to -4.6 x 10(-5) C/m(2) K. For the samples cut from the (100) sector, pronounced anomalies were revealed at 85 and 275 K, which, in our opinion, can be due to the contribution of associates formed by the coordination tetrahedra PO4(1) and PO4(2) and interstitial rubidium Rb-i . At T > 280 K, superionic conductivity begins to manifest itself in all of the samples studied, which indicates the decomposition of the dipole complexes with increasing temperature. From the measured pyroelectric coefficient and birefringence along the polar direction, the spontaneous polarization of rubidium titanyl is calculated to be 0.5 C/m(2) at 250 K, which is comparable in magnitude to that of lithium tantalate.