GROWTH AND DIELECTRIC PROPERTIES OF TA_(2)O_(5) SINGLE CRYSTAL FIBERS

摘要

Single crystal fibers of Ta_(2)O_(5) have been grown by the Laser Heated Pedestal Growth (LHPG) technique up to several cm in length with diameters of 1.1 mm. The as grown crystal, characterized by X-ray diffraction, dielectric measurement and thermal expansion analysis, has H_(tri)-Ta_(2)O_(5) symmetry. Dielectric permittivity, loss tangent along [001] and [110] direction were investigated over the temperature range from -180 deg C to 100 deg C. Large dielectric anisotropy in Ta_(2)O_(5) single crystal was observed. At room temperature, the dielectric permittivity (1 MHz) along the [001] is 33.2, while that along the [110] is 231.9. The reason of dielectric enhancement in Ta_(2)O_(5) crystal grown by LHPG was also discussed.