Preparation Of Ferromagnetic/Ferroelectric Composite Fibres By Organic Gel-thermal Decomposition Process

The xCoFe₂O₄-(1-x)BaTiO₃(x=0.2,0.3,0.4,0.5) and Ni_xCo_1-xFe₂O₄-BaTiO₃ (x=0.8,0.7,0.6,0.5) ferromagnetic/ferroelectric composite fibers have been prepared by the organic gel-thermal decomposition process from the raw materials of citric acid and metal salts.The gel precursors of CA-Co-Fe-Ti-Ba,CA-Ni-Co-Fe-Ti-Ba were characterized by Fourier-Transform Infrared Spectroscopy(FT-IR).It is reasoned that the carboxylic radiacl ligand combines with metal ions in the aqueous solution by a single dentate model and the gel precursors are linear-type structural molecules.These gel precursors with a linear type structure exhibited a good spinnability,the gel precursors could make long gel fibres.The transformation of gel fibre precursors and products under different temperatures have been investigated by Thermo-Gravimetric and Differential Scanning Calorimeter(TG-DSC),Fourier-Transform Infrared Spectroscopy(FT-IR) and X-Ray Diffraction(XRD).The morphologies of the fibers derive from thermal-decomposition of the gel precursors were characterized by Scanning Electron Microscopy(SEM).The nano-composite fibers were also characterized by Vibrating Sample Magnetometer(VSM) and the parameters of saturation magnetiation,coercive force and hysteresis loops were obtained.On another way,the method of preparing 1-3 type magnetoelectric materials by epoxy and nano-composite fibers have been explored.The reasons and the improvement for the bubble in the 1-3 type magnetoelectric material have been examined and these 1-3 type magnetoelectric materials were characterized by Vibrating Sample Magnetometer(VSM) and the magnetic anisotropy have been investigated.The experiment results indicate that the nano-composite fibers as prepared are characterized with diameters as thin as 1μm,a high aspect ratio up to 1×10⁵,and a dense surface.The saturation magnetization of nano-composite fibers is mainly effectted by the molar fraction and grain size of ferromagnetic phase,the coercive force is influenced by the grain size of ferromagnetic phase.