Study on structural, conduction mechanisms, and non-Debye behavior of YbNbO4 ceramic: insights into charge carrier dynamics

Abstract

Rare-earth orthoniobates have attracted significant attention due to their multifunctional properties and potential in advanced technological applications. In this work, YbNbO4 ceramic was prepared by a conventional solid-state reaction method. X-ray diffraction analysis confirms the formation of a single-phase monoclinic structure with I2/a symmetry. Scanning electron microscopy reveals a dense microstructure with well-defined grains, while EDX analysis confirms the expected stoichiometry and elemental homogeneity. The electrical properties were investigated using complex impedance spectroscopy in the frequency range 0.5 Hz–1 MHz and temperature interval 553–653 K. The impedance spectra exhibit depressed semicircles, indicating a non-Debye type relaxation. The electrical response is well fitted by an equivalent circuit model (R//C//CPE + CPE), suggesting contributions from both grain and grain boundary effects. The material shows semiconducting behavior with a negative temperature coefficient of resistance. The AC conductivity follows Jonscher’s universal power law. The activation energy (~ 0.41 eV), obtained from DC conductivity, indicates a thermally activated conduction process. The temperature dependence of the frequency exponent (s) supports the correlated barrier hopping (CBH) model. Low dielectric loss values, particularly at low frequencies, highlight the good dielectric stability of the material. The results highlight its potential as a promising multifunctional material for applications in electronic and energy storage devices.