Dielectric and impedance analysis of la doped-TbMnO₃

In the present work, the authors report the results of the dielectric properties of La doped TbMnO₃ samples, which have remain relatively uninvestigated. With the complex impedance analysis technique adopted, dielectric properties of the samples as a function of temperature (110K≤T≤300K) and frequency (1Hz≤f≤10MHz) were measured. The high dielectric constant (HDC) effect was observed at the high temperature and low frequency regions. Two relaxation peaks emerged at the low and high-frequency regions, respectively. Generally, it would be inferred that the peaks correlated with the HDC behavior are due to the Maxwell-Wagner (M-W) polarization effect. We consider that the HDC effect is tightly linked with the grain and grain boundaries' M-W polarization, often referred to as the internal barrier-layer capacitor (IBLC), and the electrode-bulk interfacial M-W polarization on the low and high temperature regions, respectively. Our results are helpful in providing further insight into the origin of dielectric properties in the perovskite oxide system.