Institute of Materials Science, University of Silesia, ulica Bankowa 12, PL 40-007 Katowice, Poland.
J Phys Condens Matter. 2011 Apr 20;23(15):155901. doi: 10.1088/0953-8984/23/15/155901. Epub 2011 Apr 1.
Linear and nonlinear dielectric measurements of AgNbO₃ ceramics and single crystals were carried out for the M phases (77-673 K). The linear dielectric response is dominated by the contribution of the submillimetre relaxational mode related to the Nb⁵+ ion dynamics (M₂-M₃). On the other hand, nonlinear dielectric χ₃' susceptibility revealed anomalies at three characteristic temperatures: 90, 325 and 448 K. Two later ones are connected with changes of the Nb⁵+ ion dynamics. At T(f) = 448 K a partial freezing of the Nb⁵+ ion displacement to the anti-polar, antiferroelectric array takes place. At 325 K further freezing of Nb and Ag displacements to the polar weak relaxor ferroelectric or dipolar glass transition occurs. This polar state coexists with the ground antiferroelectric one.
对 M 相（77-673 K）的 AgNbO3 陶瓷和单晶进行了线性和非线性介电测量。线性介电响应主要由与 Nb5+离子动力学相关的亚毫米波弛豫模式的贡献（M2-M3）决定。另一方面，非线性介电 χ₃' 磁化率在三个特征温度处显示出异常：90、325 和 448 K。后两个与 Nb5+离子动力学的变化有关。在 T(f) = 448 K 时，Nb5+离子位移到反极性、反铁电阵列的部分冻结发生。在 325 K 时，Nb 和 Ag 位移进一步冻结到极性弱弛豫铁电或偶极子玻璃转变发生。这种极性状态与基态反铁电状态共存。
