Structure, ferroelectric, piezoelectric and ferromagnetic properties of BiFeO_3-Ba_(0.85)Ca_(0.15)Ti_(0.90)Zr_(0.10)O_3 lead-free multiferroic ceramics

摘要

Lead-free (1-x)BiFeO_3-xBa_(0.85)Ca_(0.15)Ti_(0.90)Zr_(0.10)O_3+1 mol% MnO_2 multiferroic ceramics have been prepared by a conventional ceramic fabrication technique and their structure, ferroelectric, piezoelectric and ferromagnetic properties have been studied. Ba_(0.85)a_(0.15)(Ti_(0.9)Zr_(0.1))O_3 diffuses into the BiFeO_3 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 Ba_(0.85)Ca_(0.15)(Ti_(0.9)Zr_(0.1))O_3. The ferroelectric and piezoelectric properties of the ceramics are improved. For the ceramic with x=0.275, the piezoelectric properties become optimum: d_(33)=106 pC/N and k_p=29.7%. The ceramics also exhibit weak magnetic properties.