X-ray structure refinement and pyroelectric investigation of fresnoite, Ba2TiSi2O8

摘要: Crystal structure parameters have been refined from single crystal x-ray intensity data collected on Ba2TiSi2O8 at 24 and 300°C. Anisotropic refinements in space group P4bm yielded residuals of 0.035 0.042 300°C, respectively. Pyroelectric measurements give a room temperature pyroelcctric coefficient + 10 μC m -2 K -1. A structural mechanism for the pyroelectric effect is discussed terms large oxygen displacements. sign reversal pyroeleetric occurs 160°C, perhaps caused by cancellation primary secondary effects.