Evaluation of material constants in NdCa4O(BO3)3 piezoelectric single crystal

Abstract

A neodymium calcium oxoborate NdCa4O(BO3)3 piezoelectric single crystal that belongs to the monoclinic system with point group m was grown by the Czochralski technique. A practical evaluation method was developed to determine the 27 independent material constants for acoustic wave device applications. A longitudinal effect face–shear vibration was analyzed and used in the resonance–antiresonance measurement. This method avoided measuring d 11 and d 33 directly by use of X-bar and Z-bar, in which leak of electric field would cause large errors because of the very small dielectric constants. At room temperature, dielectric constants were $${{\varepsilon _{11}^{\text{T}} } \mathord{\left/{\vphantom {{\varepsilon _{11}^{\text{T}} } {\varepsilon _0 }}} \right.\kern-\nulldelimiterspace} {\varepsilon _0 }} = 9.9$$ , $${{\varepsilon _{22}^{\text{T}} } \mathord{\left/{\vphantom {{\varepsilon _{22}^{\text{T}} } {\varepsilon _0 }}} \right.\kern-\nulldelimiterspace} {\varepsilon _0 }} = 15$$ , $${{\varepsilon _{33}^{\text{T}} } \mathord{\left/{\vphantom {{\varepsilon _{33}^{\text{T}} } {\varepsilon _0 }}} \right.\kern-\nulldelimiterspace} {\varepsilon _0 }} = 10$$ and $${{\varepsilon _{13}^{\text{T}} } \mathord{\left/{\vphantom {{\varepsilon _{13}^{\text{T}} } {\varepsilon _0 }}} \right.\kern-\nulldelimiterspace} {\varepsilon _0 }} = - 0.8$$ , respectively. All the independent dielectric and elastic constants were determined in this work. The simulation of surface acoustic wave velocity showed a good agreement with the measured value.