Multiferroic properties of single-phase Bi_0.85La _0.15FeO₃ lead-free ceramics

Single-phase and lead-free Bi_0.85La_0.15FeO ₃ multiferroic 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/cm² together 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 Bi_0.85La_0.15-FeO₃ permitted 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.