Dielectric and electrical properties of undoped and Fe-doped yttrium copper titanate

Abstract

Y2/3Cu3Ti3.90Fe0.10O12 (YCTFO) nano-ceramic was synthesized by semi-wet route. Polycrystalline phase of YCTFO was characterized by XRD. Scanning electron micrograph revealed the presence of smooth surface bimodal spherical grains having size in between 0.5-1.5 um along with a few irregular shaped large grains having size 1.5-2.8 um. EDX spectral analysis confirmed its stoichiometric purity while bright field TEM image confirmed the presence of polycrystalline, well dispersed particles with some agglomeration. The presence of a few clear rings in its corresponding SAED pattern again confirmed the formation of polycrystalline stable YCTFO. Dispersion in ac conductivity with frequency was observed which gets narrower with increase in temperature. The calculated values of hopping parameters s1 and s2 suggest that the conduction in YCTFO ceramic is due to overlapping large polaron tunnelling mechanism. YCTFO exhibits high dielectric constant with temperature dependent Maxwell Wagner relaxation. The impacts of acceptor type of hetero-valent substitution of Ti4+ by Fe3+ were reflected as decrease in grain size and broadening of ε1-T peak with simultaneous decrease in ε1-value. Copyright © 2015 by the American Ceramic Society. All rights reserved.