Observation of room temperature multiferroicity in CuO-doped Sr3Bi4Ti6O21 lead-free ferroelectric ceramics

Abstract

Room temperature multiferroicity was achieved in CuO-doped Sr 3 Bi 4 Ti 6 O 21 (SBT 6 ) lead-free bismuth layered structure ferroelectric ceramics. On addition of CuO, a feeble magnetization with highest saturation magnetization of * 3 memu/g and least coercivity of 676 Oe was obtained for x = 0.5 mol% sample. The effect of magnetic field on the ferroelectric properties was investigated, which reveals the presence of magnetoelectric (ME) coupling indirectly and the maximum remnant polarization of 12.16 lC/cm 2 at 1 kOe was obtained. Moreover, from direct measurements (ME studies), coupling between ferromagnetic and ferroelectric phases was also achieved at room temperature. Further, the presence of feeble ME effect decreases upon increasing CuO doping concentration, especially at higher doping concentration. The induced spontaneous magnetization, oxygen vacancies and strong magnetic superexchange interaction of CuO played a key role in achieving room temperature multiferroicity.