Investigation of microwave dielectric relaxation process in the antiferroelectric phase of NaNbO_3 ceramics

摘要

This letter reports microwave dielectric measurements performed in the antiferroelectric phase of NaNbO_3 ceramics from 100 to 450 K. Remarkable dielectric relaxation was found within the antiferroelectric phase and in the vicinity of the ferroelectric-antiferroelectric phase transition. Such dielectric relaxation process was associated with relaxations of polar nanoregions with strong relaxor-like characteristic. In addition, the microwave dielectric measurements also revealed an unexpected and unusual anomaly in the relaxation strength, which was related to a disruption of the antiferroelectric order induced by a possible AFE-AFE phase transition.