Study On Preparation And Properties Of CFO/PMN-PT Multiferroic Ceramics

In this paper, 0.67Pb(Mg1/3Nb2/3)O3-0.33 Pb Ti O3 was selected as a piezoelectric phase due to its hightest piezoelectric and Co Fe2O4 was selected as the piezomagnetic phase due to its high magnetostrictive which has the largest magnetostrictive properties of all the ferrite. Traditional solid method is used to prepare different components of x CFO/(1-x)PMN-PT composite ceramics(x =0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9).We optimize the preparation technology of CFO/PMN-PT composite ceramics to improve the density. We also explore the influence of the preparation technology and the composition to its ferroelectric property, ferromagnetic property and magnetoelectric coupling property.In the process of the preparation of composite ceramics, we add granulation and cold isostatic pressing process to improve the density of composite ceramics as well as the ferroelectric properties of composite ceramics. When the CFO content of the composite ceramic is 10 mol.%, its biggest saturated polarization increases from 11.3μC/cm2 to 16 μC/cm2.Compared with ordinary pressureless sintering, oxygen atmosphere sintering can significantly increase the density of composite ceramics, when the CFO content of the composite ceramic is 10 mol.%, the density of the composite ceramic increaseed by96.2%. The leakage current of the composite ceramic also reduces sintering at oxygen atmosphere, and when the CFO content of the composite ceramic is 10 mol.%, the leakage current reduces from 7.15×10-5A to 5.34×10-8A at 4V. Oxygen atmosphere sintering is also useful of improving the composite ceramic ferromagnetism, when the CFO content of the composite ceramic is 10 mol.%, the saturated polarization Ms increased by 15.43%.The composite ceramic has the highest density, the best ferroelectric and ferromagnetic properties when the holding time under oxygen atmosphere sintering is1 h. The best sintering temperature rises with the increase of the content of CFO. When the sintering temperature is higher, the x CFO/(1-x)PMN-PT(x<0.5) composite ceramics has better ferroelectric property, while x CFO/(1-x)PMN-PT(x>0.5) composite ceramics has poorer ferroelectric property. With the increase of sintering temperature, the ferromagnetic property of composite ceramics reaches a maximum value and then decreases.Along with the increase of the content of ferromagnetic phase CFO, the leakage current of CFO/PMN-PT composite ceramics increases gradually, and the ferroelectric property reduces while the ferromagnetic property enhanced gradually. The magnetoelectric effect can be detected in the composite ceramic which density reaches more than 95%. When the CFO content of the composite ceramic is 10 mol.%, we get the maximum transverse magnetoelectric voltage coefficient 66.77μV/cm·Oe under an applied magnetic field of 390 Oe.