Growth and piezoelectric properties of TmCOB single crystals

New rare-earth oxyborate crystals TmCOB were grown by using the Czochralski method. The piezoelectric coefficients for TmCOB were determined to be on the order of d₁₁=1.7, d₁₂=3.8, d₁₃=-4.2, d₁₅=-0.92, d₂₄=4.9, d₂₆=7.8, d₃₁=-0.75, d₃₂=-2.4, d₃₃=2.2 and d₃₅=-5.2 pC/N. The temperature dependence of electro-elastic propertieswereinvestigated from 20 to 900°C, where the temperature coefficients of the elastic compliances (s^E₂₂, s^E₃₃ and s^E₆₆) were foundto be ranged from 146 to223 ppm/°C for TmCOB crystals. Particularly, the electromechanical factor k₁₂ was evaluated to be on the order of 15.4% at room temperature, with a small variation <;5.4% in the temperature range of 20-900°C. Moreover, the TmCOB crystals were obtained to possess high piezoelectric coefficientd₂₆ being 7.8 pC/N, 3-4 times that of quartz, and showing a minimal variation of -12.9% over the test temperature range, potential for high temperature piezoelectric applications.