Studies On Preparation And Properties Of SrTiO₃-CoFe₂O₄Composite Ceramic By Sol-gel Process

Multiferroic composite ceramic materials is one of mutiferroics, which shows a couplingmagnetoelectric （ME） effect by the coupling magnetic-mechanical-electric interaction. Andrefers to a certain temperature range, which two or more to show the basic properties of ironmare. Such as: ferroelectric（anti-ferroelectric）, ferromagnetic（anti-ferromagnetic） or ironflexibility. Use of magnetoelectricity coupling effect can realize magnetoelectricity orelectromagnetic phenomena conversion, in the new magnetoelectricity storage,magnetoelectric sensor, energy conversion system and many other high technology fields hasa broad prospect of application.In this paper, SrTiO₃, BaTiO₃single-phase powder and xSrTiO₃-（1-x）CoFe₂O₄compositepowder were prepared by sol-gel process. And we made the datailed study of its structures,magnetic, ferroelectric and dielectric. Phases were characterized by X-ray diffraction meter.Ferroelectric, dielectric, and magnetic property of the powder were analysis using tfanalyzer2000, agilent4294A and physical comprehensive performance system （PPMS）.For the single phase ceramic of SrTiO₃and BaTiO₃was found that, all the samples arealready formed perovskite phase. SrTiO₃powder compared to SrTiO₃powder, both of themare cubic structure. But the dielectric constant value of the SrTiO₃powder smaller than thedielectric constant of the BaTiO₃powder, the dielectric value of SrTiO₃powder is greaterthan the BaTiO₃powder, at the same time, remaining polarization strength and overcomingthe field more than BaTiO₃powder.For the single phase ceramic of CoFe₂O₄experimental results show that the diffractionpeak is belong to the cubic phase of the CoFe₂O₄ceramic, no dephasign can be detected, atroom temperature can obtain the ferromagnetic and magnetic very strong also. Through theferroelectric test and dielectric test, CoFe₂O₄ceramic has weak ferroelectricity. This explainCoFe₂O₄ceramic is the good performance of magnetic materials and contribute to improvethe magnetic of composite ceramic materials and ferroelectricity.For the single phase ceramic of experimental results have found that the diffraction peakis belong to the cubic phase both of the SrTiO₃ceramic and CoFe₂O₄ceramic, no dephasign can be detected, at room temperature can obtain the ferromagnetic, with the increase of thecontent of CoFe₂O₄magnetic first decreases enhanced the dielectric constant are obviouslysmaller than the SrTiO₃ceramic, dielectric values slightly increased compared with SrTiO₃ceramic samples. And the remanent polarization of the composite ceramic samples isstrengthened with the addition of CoFe₂O₄, restrain the leakage current effectively, in otherwords, ferroelectricity is improved with the CoFe₂O₄content increase.