Study on the structural and electrical properties of YMnO3 co-substituted with transition metal ions at Mn-site and their conduction mechanism

• Published in: Journal of materials science. Materials in electronics 2022-03, Vol.33 (9), p.6107-6120
• Main Authors: Chanu, Lisham Paris, Phanjoubam, Sumitra
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Materials Science; Optical and Electronic Materials
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-022-07788-8

Rare earth manganite YMnO 3 and YMn 0.9 Cr 0.06 Fe 0.04 O 3 wherein transition metal ions are co-substituted at Mn-sites, were synthesized via sol–gel auto combustion route. The present work aims to study the effect of Cr 3+ and Fe 3+ co-substitution at Mn-site of YMnO 3 , on their structural and electrical properties. The structural and morphological studies were performed using X-ray diffraction (XRD), Raman spectroscopy, and field emission scanning electron microscopy (FESEM). The XRD pattern confirmed the existence of monophasic hexagonal structure for YMnO 3 while the onset of few orthorhombic peaks was observed for YMn 0.9 Cr 0.06 Fe 0.04 O 3 . The A 1 Raman scattering line at ∼ 676 cm −1 was observed to be much stronger than the other Raman modes. Uniform and dense morphological structure were observed in the FESEM micrographs. Enhanced dielectric properties were observed in the substituted sample. The frequency dependence of AC conductivity was investigated using Jonscher’s law. Non-overlapping small polaron tunnelling model was predicted for the conduction model in YMnO 3 and correlated barrier hopping in YMn 0.9 Cr 0.06 Fe 0.04 O 3 to elucidate the conduction mechanism of the system. The activation energy for intrinsic charge carriers was calculated using Arrhenius equation. The impact of grains and grain boundaries on the electrical behaviour of the samples was validated by fitting the Nyquist plot.