Li_(0.025) Na_(0.975) NbO_3单晶的介电压电热释电和铁电性

THE DIELECTRIC PIEZOELECTRIC PYROELECTRIC AND FERROELECTRIC PROPERTIES OF Li_(0.025) Na_(0.975) NbO_3 SINGLE CRYSTAL

报告了Li_(0.025)Na_(0.975)NbO_3单晶的一些性能,测量表明该晶体的点群为mm2,其自发极化强度和矫顽场分别是P_s=2.6×lO^(-2)C/m^1与E^c=l.5KV/mm,极化后样品的压电应变常数和热释电系数分别是d_(33)=24×10^(-12)C/N与P=3.2×10_(-5)C/m~·K,室温下样品介电谱的测量表明、晶体在300MHz附近出现了介电驰豫,由样品极化后的ε'_(33)-f曲线得出其厚度振动机电耦合系数k_t=O.32.

Report on the dielectric piezoelectric pyroelectric and ferro-electric properties of Li_(0.025) Na_(0.975) NbO_3 single crystal. The point gr-oup of this single crystal has been determined to be mm2. The spontaneous polarization and coercive field at room temperature respectively P_s=2.6× 10^(-2)/m^2, E_e=1.5kv/mm. The poled samples have piezoelectric constant d_33=24×10^(-12)C/N and pyroelectric coefficient P=3.2×10^(-5)C/m^2·k at room temperature. Dielectric spectroscopy of theSe samples reveals that the crystal has a dielectric relaxation at about 300 MHz. The thickness vibrati-on electromechanical coupling factor obtained from E_(33)~′-f curve is k_t=O.32.