Dielectric properties of TbMnO3 ceramics doped with Bi and Fe ions

The ceramic composites of TbMnO3, Tb0.95Bi0.05MnO3, Tb0.9Bi0.1MnO3 and Tb0.9Bi0.1Mn0.95Fe0.05O3 were compounded by conventional solid-state reaction. Both dielectric constants (ɛ′) and loss tangent (tanδ) of composites have been measured and studied as a function of the temperature from 80 to 400 K and the frequency from 100 Hz to 1 MHz. Interestingly, doping Bi makes dielectric constant decrease and the dielectric dissipation peaks disappear in the high temperature range. But the dielectric constant becomes larger and the dielectric dissipation peaks appear again in the high temperature range after Fe doping appropriately. Analysis indicates that the perovskite structures gradually vary with the increase of Bi replacing Tb, thus the dielectric properties could be enhanced with the small amount of Mn replacement with Fe.