Ionic Conductivity of KTiOPO4 Single Crystals Grown by Flux Crystallization under Different Conditions

The ionic conductivity of three KTiOPO4 crystals grown from high-temperature solution-melts in combination with the Czochralski technique under different conditions has been investigated. The first crystal was obtained at a cooling rate V-g = 0.2-0.5 mm/day and a ratio of potassium and phosphorus concentrations in the solution-melt [K]/[P] = 2. The other two crystals were grown at a much higher velocity (V-g = 3-7 mm/day) from solution-melts with [K]/[P] = 1.5 and 1. It is shown that the crystal grown upon slow cooling at [K]/[P] = 2 has the lowest ionic conductivity: sigma(||c) = 1.0 x 10(-5) and 3 x 10(-11) S/cm at 573 and 293 K, respectively.