Rationalization of dielectric properties of nano-sized iron doped yttrium copper titanate using impedance and modulus studies

Iron doped Yttrium Copper Titanate nano-ceramic with composition, Y2/3Cu3Ti3.90Fe0.10O12 (YCTFO) was prepared by semi-wet route. It displays all normal XRD peaks of Y2/3Cu3Ti4O12 (YCTO) along with a few secondary peaks of CuO. Stoichiometric purity of the composition was ascertained by EDX spectral analysis. The distribution of bimodal spherical grains confirms 0.5–1.5 µm size limit along with a few irregular shaped large grains with size 1.5–2.8 µm. The impacts of acceptor type of hetero-valent substitution of Ti4+ by Fe3+ in Y2/3Cu3Ti4O12 (YCTO) were reflected as decrease in grain size and broadening of εr–T peak with simultaneous decrease in εr value. The presence of temperature dependent relaxation was also rationalized by impedance and modulus spectroscopic studies which confirm ferroelectric to paraelectric phase transition at 348 K.