Dielectric characteristics of Si-added and Si-doped TbMnO3

Polycrystalline Si-added TbMnSixO3 (x=0.05, 0.1) and Si-doped Tb1−xMnSixO3, TbMn1−xSixO3 (x=0.05, 0.1) samples were fabricated by a conventional solid-state reaction. The dielectric properties of ceramics have been investigated in a temperature range of 77–350 K and a frequency range of 0.1−200 kHz. Especially, an extraordinarily high low-frequency dielectric constant (~105) at room temperature was observed in TbMnSi0.1O3, and the values of ε′(T)ε′(T) at other frequencies can reach around 104. It turns out that the addition of element Si changes dielectric properties of TbMnO3 remarkably. Through the measured data of complex impedance, bulk contribution and grain boundary effects to electrical response are identified by the analysis of complex plane diagrams (Nyquist diagram).