Structural and electrical transport studies in Bi-substituted Yttrium Chromite

Abstract

Perovskite type chromites are studied recently for their fascinating structure and inter-related functional properties. YCrO3 (YCO) is one among the chromites which possess structural heterogeneity. The structural studies on YCrO3 (YCO) and Y0.9Bi0.1CrO3 (YBiCO-10) reveal that the powder diffraction patterns exhibits a single phase with orthorhombic Pnma space group. Compositional studies on YCO and YBiCO-10 indicates the cation ratios of (Y, Bi):Cr (1:1) is preserved. Microstructural studies reveal that there is an increment in grain growth in YBiCO-10 ceramics. The microstructural studies also evidently show that YBiCO-10 has more of faceted orthorhombic type of grains, whereas, YCO has a spherical grain type of features. Impedance spectroscopy studies were performed on both YCO and YBiCO ceramics and the studies reveal a significant change in grain resistance. The decrease of resistance could be due to increase of grain size which offers the conductive path of hopping of charge carriers or inherent electrical transitions of Cr3+ in YBiCO-10 sample. These chromites can be used as potential candidates for the thermistor applications whose thermistor parameter (β) and sensitivity (α) values are 2873 K, −5 × 10− 3 K−1 (YCO) and 3102 K,−5.44 × 10− 3K−1 (YBiCO-10) at 755 K.