Impact of Ba/Ti ratio on the magnetic properties of BaTiO3 ceramics

Bulk BaTiO3 ceramics are prepared by solid state reaction route by varying Ba/Ti ratio from 0.990 to 1.005 in steps of 0.005 to study the influence of Ba/Ti ratio on the origin of ferromagnetism in the otherwise diamagnetic material. Structural investigation confirmed the coexistence of two-phase structural model, tetragonal (P4mm) + orthorhombic (Amm2) using Rietveld refinement program. For the first time, structural defect of Ti vacancies are quantified using refinement while the Ba and O are fully occupied. Room temperature magnetic M-H measurements have indicated that the diamagnetic-like and ferromagnetic-like loops in Ti-rich and Ti-deficient BaTiO3 system respectively. The ferromagnetic-like behavior (Ti-deficient) is originated from the intrinsic defect that is Ti vacancy which plays a decisive role in the magnetic property of otherwise diamagnetic BaTiO3 ceramics. Magnetodielectric constant is negligible in Ti-rich samples while high value of magnetodielectric constant is obtained as - 0.88% at 0.8T in Ba/Ti = 1.005 sample.