Multiferroic properties of single-phase Bi_0.85La_0.15FeO₃lead-free ceramics

Single-phase and lead-free Bi0.85La0.15FeO3multiferroic ceramics were prepared by a rapid liquid sintering method to study their crystal structure and multiferroic behaviors. Rietveld refinement of X-ray diffraction data showed a pseudo-cubic structure plus a small triclinic distortion. The absence of Fe2+ions suggested few oxygen vacancies. Large polarizations of 20.3 μC/cm2together with a piezoelectric d33coefficient of ∼27.7 pC/N were achieved. This ferroelectricity originates from the stereochemical activity of the A-site Bi3+lone electron pair. The remnant magnetizations of 0.0744-0.227 emu/g of Bi0.85La0.15-FeO3permitted by the canting angle of canted antiferromagnetic order was released as a result of the collapse of the space-modulated spin structure of BiFeO3. The observed dielectric anomalies proved the magnetoelectric couplings between ferroelectric order and canted antiferromagnetic order.