Author: Shaldin Yu. Matyjasik S. Novikova N. Tseitlin M. Mozhaev E. Roth M.
Publisher: MAIK Nauka/Interperiodica
ISSN: 1063-7745
Source: Crystallography Reports, Vol.55, Iss.6, 2010-11, pp. : 1012-1018
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Abstract
The temperature dependences of the pyroelectric coefficients of KTiOAsO4 and RbTiOAsO4 single crystals grown by flux crystallization have been investigated in the temperature range of 4.2-300 K. With an increase in temperature, superionic conductivity first arises in KTiOAsO4 (at T > 200 K) and then (at T > 270 K) in RbTiOAsO4. This conductivity is much higher in the samples polarized at T = 4.2 K. An exponential change in the crystal resistivity along the polar direction is simultaneously observed. The results of measurements in the range of 4.2-200 K indicate larger values of pyroelectric coefficients when compared with potassium and rubidium titanyl-phosphate crystals. A correlation between the pyroelectric coefficients and a change in the lattice constants at isomorphic substitutions of K atoms for Rb and P atoms for As has been revealed within the symmetry approach.