Dielectric and impedance analysis of La doped-TbMnO3

► There is La-doped effects in TMO on dielectric properties. ► Our results indicate that the dielectric properties are linked with Maxwell–Wagner relaxation mechanism. ► The impedance technique is used to analysis the origin of dielectric properties of La-doped TMO. 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.