摘要
(YxBi_(1-x))_(2/3)Cu_(3)Ti_(4)O_(12)(x=0.00-0.30)ceramics were successfully prepared via the conventional solid-state method.X-ray powder diffraction confirmed the lattice constant gradually decreases with increasing Y^(3+)content.SEM images displayed Y^(3+)substitution for Bi^(3+)gave rise to the large abnormal grains,and the size of abnormal grains became larger with the increase of Y^(3+)substitution.(YxBi_(1-x))_(2/3)Cu_(3)Ti_(4)O_(12)ceramics presented the relatively high dielectric constant of 7400 with the dielectric loss of 0.055 when x=0.20.The analysis of complex impedance suggested the grains are semiconductive and the grain boundaries are insulating.For pure Bi_(2/3)Cu_(3)Ti_(4)O_(12)ceramics,the appearance of additional low-frequency peaks in electrical modulus indicated the grain boundaries are heterogeneous.The investigation of modulus peaks fitting with Arrhenius formula implied that the low-frequency permittivity for all(YxBi_(1-x))_(2/3)Cu_(3)Ti_(4)O_(12)ceramics was ascribed to the Maxwell-Wagner relaxation at grain boundaries.In addition,a set of clear dielectric peaks above 200℃associated with Maxwell-Wagner relaxation can be found for all(YxBi_(1-x))_(2/3)Cu_(3)Ti_(4)O_(12)ceramics in the temperature dependence of dielectric constant.This set of clear dielectric peaks showed a tendency to shift to higher temperatures with the increase of Y^(3+)substitution.Meanwhile,a tiny dielectric anomaly at room temperature was found in Y-doped Bi_(2/3)Cu_(3)Ti_(4)O_(12)ceramics.
基金
This work was supported by National Natural Science Foundation of China(NSFC)(Grant Nos.51902193 and 11974275)
The Shaanxi Province Key Science and Technology Innovation Team Project(Grant No.2019TD-026)
Natural Science Basic Research Plan in Shaanxi Province of China(2019JQ-092)
the China Postdoctoral Science Foundation(2019M663617 and 2019TQ0191)
Scientific Research Plan Projects of Shaanxi Province Education Department(CN)(20JK0755).
