Bizarre dielectric anomalies in magnetoelectric composites of CoFe2O4 and BaTi0.9Zr0.1O3

Abstract

The magnetoelectric (ME) composites containing cobalt ferrite as the magnetic phase and Zr substituted (10 atomic % occupancy) barium titanate as the ferroelectric counterpart having the general formula (x) CoFe2O4 + (1 - x) BaTi0.9Zr0.1O3 (where x = 0, 0.25, 0.50, 0.75 and 1) have been synthesised by the conventional solid state diffusion route. Powder x-ray diffraction of thus prepared materials confirms the presence of ferrite and ferroelectric phases and their concurrent existence in all three composites without showing traces of any superfluous phase. Dielectric measurements have been recorded as a function of frequency (ranging from 100 Hz to 1 MHz) at room temperature and temperature (from 325 K up to a maximum of 825 K). In composites, relative permittivity and loss tangent curves with variable temperature show upsurge of bizarre anomalies which can be associated to the defect modes existing in the form of oxygen ion vacancies rather than ascribing it to the benchmark ferro to paraeletric transition. Show more