Search

Pyroelectric properties of orthorhombic Bi2ZnB2O7 (BZBO) crystals were investigated by using the charge integration method. The primary and the secondary pyroelectric coefficients of BZBO crystals were found to be 6.4 and &minus, 6.5 &micro, C/(m2&middot, &deg, C), respectively. The pyroelectric performance was evaluated by different figure of merits (FOMs), where BZBO crystals possessed relatively high current responsivity Fi (10.38 pm/V), and detectivity Fd (11.31 &times, 10&minus, 5/Pa1/2). In addition, the temperature dependent behaviours of primary pyroelectric coefficients and FOMs were studied from 15 &deg, C to 155 &deg, C, the pyroelectric properties were found to decrease with increases in temperature.

The non-centrosymmetric bismuth-based oxyborate crystals have been extensively studied for non-linear optical, opto-electric and piezoelectric applications. In this work, single crystal growth and electro-elastic properties of &alpha, BiB3O6 (&alpha, BIBO) and Bi2ZnB2O7 (BZBO) crystals are reported. Centimeter-sized &alpha, BIBO and BZBO crystals were grown by using the Kyropoulos method. High resolution X-ray diffraction tests were performed to assess the crystal quality. The full-width at half-maximum values (FWHM) of the rocking curves were evaluated to be 35.35 arcsec and 47.85 arcsec for &alpha, BIBO and BZBO samples, respectively. Moreover, the electro-elastic properties of &alpha, BIBO and BZBO crystals are discussed and summarized, based on which the radial extensional and the face shear vibration modes were studied for potential acoustic device applications. The radial extensional mode electro-mechanical coupling factors kp were evaluated and found to be 32.0% and 5.5% for &alpha, BIBO and BZBO crystals, respectively. The optimal crystal cuts with face shear mode were designed and found to be (YZt)/&minus, 53&deg, (or (YZt)/37&deg, cut) for &alpha, BIBO crystal, and (ZXt)/&plusmn, 45&deg, cut for BZBO crystal, with the largest effective piezoelectric coefficients being in the order of 14.8 pC/N and 8.9 pC/N, respectively.

A high-quality Ba2TiSi2O8 (BTS) single crystal was grown using the Czochralski (Cz) pulling method. The thermal expansion and electro-elastic properties of BTS crystal were studied for high temperature sensor applications. The relative dielectric permittivities &epsilon, 11 T / &epsilon, 0 and &epsilon, 33 T / &epsilon, 0 were determined to be 16.3 and 11.8, while the piezoelectric coefficients d15, d31, d33 were found to be 17.8, 2.9, and 4.0 pC/N, respectively. Temperature dependence of electro-elastic properties were investigated, where the variation of elastic compliance s 55 E (= s 44 E ) was found to be &lt, 6% over temperature range of 20&ndash, 700 &deg, C. Taking advantage of the anisotropic thermal expansion, linear thermal expansion comparable to insulating alumina ceramic was achieved over temperature range up to 650 &deg, C. The optimum crystal cut with large effective piezoelectric coefficient (&gt, 8.5 pC/N) and linear thermal expansion coefficient (8.03 ppm/&deg, C) achieved for BTS crystal along the (47&deg, &phi, ) direction (&phi, is arbitrary in 0&ndash, 360&deg, ), together with its good temperature stability up to 650 &deg, C, make BTS crystal a promising candidate for high temperature piezoelectric sensors.