Synthesis And Characterization Of A New Layered Ferroelectric-Ferromagnetic Composite

Ferroelectric-ferromagnetic composite is a new type of functional material that is composed of both ferroelectric phase and ferromagnetic phase. Its magnetoelectric conversion factor (dE/dH) comes from the product effect of ferroelectric phase and ferromagnetic phase, and the product effect is called magnetoelectric effect. Because of the special properties of the composite, it has a wide and important use in the fields of microwave, electric current measurement, wide frequency band magnetic detecting and magnetic sensor.In order to explore a new kind of ferroelectric-ferromagnetic composite, the layered-pillaring oxides Si2KM3O10 (M=Nb, Ta) are prepared with inorganic oxide as Fe304 as host substance because of its special microstructure character and ferroelectric property. It is well known that Fe3O4 is a kind of ferromagnetic oxide, so that a newly ferroelectric-ferromagnetic composite with Fe3O4 intercalated into the spacing of Sr2KM3O10 can be obtained.First, Sr2KM3O10 was synthesized by solid-state reaction and then acidified to SrHM3O10. The Fe3O4 pillared metal oxide couldn't been obtained by direct ionic exchange, so stepwise ionic exchange method was adopted. Second, different amines (such as propylamine, butylamine and hexylamine) were intercalated into Sr2HNb3O10 and the position of H+ were substituted. The perovskite sheets that have high density of electric charge were propped up by amines. It makes other guest substances could be easily exchanged into the spacing between the perovskite sheets. Third, [Fe3(OCOCH3)7OH-H2O]N03 was chosen as the guest substance. Because [Fe3(OCOCH3)7OH-H20]+ and amines have approximate cationic sizes and [Fe3(OCOCH3)7OH-H20]+ can maintain the stability of perovskite sheet during the process of ionic exchange reaction. The ionic exchange product with [Fe3(OCOCH3)70H-H20]+ as the interlayed substitute was synthesized then heated in furnace to decompose organic ingredient. The product of Fe2O3 pillared Sr2KM3O10 was prefabricated. Finally, Fe2O3 pillared Sr2KM3O10 was deoxidized using vapor saturated hydrogen and the final product with Fe3O4 pillared Sr2KM3O10 wassynthesized.The experimental results were measurement with chemical analysis, electron probe microanalysis (EPMA), scanning electron microscope (SEM) analysis, X-ray diffraction (XRD) analysis, thermogravimetry (TG), differential scanning calorimetry (DSC) analysis, infrared spectroscopy (IR) analysis, and so on. The ferroelectric and magnetic properties of Fe3O4 pillared Sr2KM3O10 have been studied by rt6000hvs ferroelectric measurement system and YEW-3257 magnetization circled scanner preliminarily.