Abstract:

Through sol-gel and solid state sintering method, xNiFe₂O₄/(1-x)BaTiO₃(x=0.1, 0.2, 0.3, 0.4, 0.5, 0.6) multiferroic composites were synthesized. X-Ray diffraction(XRD) result indicates the coe-xistence of both spinel NiFe₂O₄ and pervoskite BaTiO₃ phase. Scanning electron microscopy(SEM) images show that the composites are heterogeneous structure. From the high resolution transmission electron microscopy(HRTEM) image, the interface of the two phases is obviously observed. xNiFe₂O₄/(1-x)BaTiO₃ compo-sites exhibit both ferroelectric and ferromagnetic properties and the polarization-electric field(P-E) loops indicate the ferroelectric property of the composites with the tendency of leakage. The effects of frequency on dielectric constant (ε_r) of composites show ε_r of the composites decrease with increasing the frequency and reach a constant value in the low frequency. The content of the ferromagnetic phase also has influence on the dielectric property. The magnetic measurement of the composites indicates the mangetic properties of the composites originate from NiFe₂O₄ and the magnetization of composites increases with increasing the content of NiFe₂O₄.

Key words: Multiferroic composites, BaTiO₃, NiFe₂O₄, Ferroelectric property, Ferromagnetic property