Dielectric relaxation and magnetodielectric response of mesoporous terbium manganate nanopaticles

Abstract

We report here the investigation on dielectric response, charge transport mechanism and magnetocapacitance of mesoporous perovskite Terbium Manganate (TMO) nanoparticles. TMO NPs possess relatively high specific surface area (20.9 m2 g−1) than that of general perovskite-type metal oxides. To study the dielectric/magnetodielectric response in TMO material, a capacitive system is fabricated. Impedence spectroscopy shows electrically heterogeneous nature of the material. Due to the existence of inhomogeneity at electrode-TMO interface, ideality factor is larger than unity. Various Schottky diode electrical parameters are obtained here from temperature dependent capacitance–voltage (C–V) measurements. The function of Au/TMO/Au Schottky diode system is well explained from current–voltage (I–V) characteristics study. Ferroelectric-like hysteretic behaviour is observed at and above room temperature from non-ferroelectric TMO. Presence of defect states at TMO interface layer dominates the charge conduction phenomenon. Negative magnetodielectric effect arises in heterogeneous TMO sample due to the effect of magnetic field on Maxwell–Wagner space charge at the interface. The thermionic current–voltage (I–V) characteristics of the Au/TMO/Au Schottky diode have been measured within the voltage range ± 40 V. Ferroelectric type hysteretic behaviour is observed in non-ferroelectric TMO sample.