Structural, electrical, magnetic and magnetoelectric properties of Co-doped BaTiO3 multiferroic ceramics

In this work, BaTi1-xCoxO3 (BTCO) ceramics with x = 0, 2.5, 5, 7.5 and 10 mol% have been synthesized and their structural, electrical, magnetic and magnetoelectric have been investigated. Rietveld refinement of XRD data reveals that pure BTO has pure tetragonal phase. On the other hand, between 2.5 ≤ x ≤ 7.5, BTCO shows both tetragonal as well as hexagonal phases. At x = 10 mol%, BTCO shows only hexagonal phase. The grain size of the BTCO samples is found to increase with Co doping concentration. The ferroelectric polarization and relative permittivity of BTCO samples reduce with an increase in the Co concentration. A standard magnetization equation is used for fitting the magnetic hysteresis (M-H) curve, thus deconvoluting the ferromagnetic (FM) and paramagnetic (PM) components. The saturation magnetization (Ms) gradually increases from x = 2.5 to x = 10 mol%, the value being 0.8 memu/g and 8.92 memu/g respectively. The origin of magnetization is due to the oxygen vacancies and their associated exchange interaction. The magnetodielectric coefficient (MD) shows a reducing trend from 1.80 to 0.18 for x = 2.5 to x = 10 mol% respectively. The magnetoelectric coefficient (αME) for x = 2.5 mol% is 3.399 mV/cm. Oe, while for x = 10 mol% it is 0.896 mV/cm. Oe.