Structure, ferroelectric, piezoelectric and ferromagnetic properties of BiFeO3–Ba0.85Ca0.15Ti0.90Zr0.10O3 lead-free multiferroic ceramics

Lead-free (1−x)BiFeO3–xBa0.85Ca0.15Ti0.90Zr0.10O3+1 mol% MnO2 multiferroic ceramics have been prepared by a conventional ceramic fabrication technique and their structure, ferroelectric, piezoelectric and ferromagnetic properties have been studied. Ba0.85Ca0.15(Ti0.9Zr0.1)O3 diffuses into the BiFeO3 lattices to form a new solid solution with a perovskite structure. The ceramics with x=0.15–0.275 possess a rhombohedral phase. As x increases, the ceramic transforms into a pseudo-cubic phase. A morphotropic phase boundary separating the two phases is formed at 0.275<x<0.30. A diffusive ferroelectric–paraelectric phase transition is induced in the ceramics with high concentrations of Ba0.85Ca0.15(Ti0.9Zr0.1)O3. The ferroelectric and piezoelectric properties of the ceramics are improved. For the ceramic with x=0.275, the piezoelectric properties become optimum: d33=106 pC/N and kp=29.7%. The ceramics also exhibit weak magnetic properties.