Structures and magnetic properties of nanocomposite CoFe₂O₄-BaTiO₃ fibers by organic gel-thermal decomposition process

Abstract

The nanocomposite xCoFe₂O₄-(1−x)BaTiO₃ (x=0.2, 0.3, 0.4, 0.5, molar fraction) fibers with fine diameters and high aspect ratios (length to diameter ratios) were prepared by the organic gel-thermal decomposition process from citric acid and metal salts. The structures and morphologies of gel precursors and fibers derived from thermal decomposition of the gel precursors were characterized by Fourier transform infrared spectroscopy, X-ray diffractometry and scanning electron microscopy. The magnetic properties of the nanocomposite fibers were measured by vibrating sample magnetometer. The nanocomposite fibers consisting of ferrite (CoFe₂O₄) and perovskite (BaTiO₃) are formed at the calcination temperature of 900 °C for 2 h. The average grain sizes of CoFe₂O₄ and BaTiO₃ in the nanocomposite fibers increase from 25 to 65 nm with the calcination temperature from 900 to 1 180 °C. The single fiber constructed from these nanograins of CoFe₂O₄ and BaTiO₃ has a necklace-like morphology. The saturation magnetization of the nanocomposite 0.4CoFe₂O₄-0.6BaTiO₃ fibers increases with the increase of CoFe₂O₄ grain size, while the coercivity reaches a maximum value when the average grain size of CoFe₂O₄ is around the critical single-domain size of 45 nm obtained at 1 000 °C. The saturation magnetization and remanence of the nanocomposite xCoFe₂O₄-(1−x)BaTiO₃ (x=0.2, 0.3, 0.4, 0.5) fibers almost exhibit a linear relationship with the molar fraction of CoFe₂O₄ in the nanocomposites.

Keywords

nanocomposite / CeFe₂O₄ / BaTiO₃ / fiber / organic gel-thermal decomposition process / magnetic property

References

[1] IijimaS.. Helical microtubules of graphitic carbon [J]. Nature, 1991, 354: 56-58

[2] MoralesA. M., LieberC. M.. A laser ablation method for the synthesis of crystalline semiconductor nanowires [J]. Science, 1998, 279(5348): 208-211

[3] MartinC. R.. Nanomaterials: A membrane-based synthetic approach [J]. Science, 1994, 266(5193): 1961-1966

[4] HanW.-q., FanS.-s., LiQ.-q., HuY.-dan.. Synthesis of gallium nitride nanorods through a carbon nanotube-confined reaction [J]. Science, 1997, 277(5330): 1287-1289

[5] PanZ.-w., DaiZ.-r., WangZ.-lin.. Nanobelts of semiconducting oxides [J]. Science, 2001, 291(5510): 1947-1949

[6] JuY. W., ParkJ. H., JungH. R., ChoS. J., LeeW. J.. Electrospun MnFe₂O₄ nanofibers: preparation and morphology [J]. Composites Science and Technology, 2008, 68(7/8): 1704-1709

[7] CaoK., ShenX.-q., JingM.-x., ZhouJ.-xin.. Preparation of ferromagnetic metal fine fibers by organic gel-thermal reduction process [J]. Journal of Central South University of Technology, 2007, 14(5): 607-611

[8] WangW.-z., LiuY.-k., XuC.-k., ZhengC.-l., WangG.-hou.. Synthesis of NiO nanorods by a novel simple precursor thermal decomposition approach [J]. Chemical Physics Letters, 2002, 362(1/2): 119-122

[9] ZhangC.-y., ShenX.-q., ZhouJ.-x., JingM.-x., CaoKai.. Preparation of spinel ferrite NiFe₂O₄ fibres by organic gel-thermal decomposition process [J]. Journal of Sol-Gel Science and Technology, 2007, 42(1): 95-100

[10] XiangJ., ShenX.-q., MengX.-feng.. Preparation of Co-substituted MnZn ferrite fibers and their magnetic properties [J]. Materials Chemistry and Physics, 2009, 114: 362-366

[11] SriniyasS., LiJ. Y.. The effective magnetoelectric coefficients of polycrystalline multiferroic composites [J]. Acta Materialia, 2005, 53: 4135-4142

[12] HuaZ., YangP., HuangH.. Sol-gel template synthesis and characterization of magnetoelectric CoFe₂O₄/Pb(Zr_0.52Ti_0.48)O₃ nanotubes [J]. Materials Chemistry and Physics, 2008, 107: 541-546

[13] XieS. H., LiJ. Y., LiuY. Y., LanL. N., JinG., ZhouY. C.. Electrospinning and multiferroic properties of NiFe₂O₄-Pb(Zr_0.52Ti_0.48)O₃ composite nanofibers [J]. Journal of Applied Physics, 2008, 104: 024115

[14] XiaoS.-h., JiangW.-f., LiL.-y., LiX.-Jian.. Low-temperature auto-combustion synthesis and magnetic properties of cobalt ferrite nanopowder [J]. Materials Chemistry and Physics, 2007, 106: 82-87

[15] ZhangS.-p., DongD.-w., SuiY., LiuZ.-g., WangH.-x., QianZ.-n., SuW.-hui.. Preparation of core shell particles consisting of cobalt ferrite and silica by sol-gel process [J]. Journal of Alloys and Compounds, 2006, 415: 257-260

[16] RamajoL., ParraR., ReboredoM.. Heating rate and temperature effects on the BaTiO₃ formation by thermal decomposition of (Ba,Ti) organic precursors during the Pechini process [J]. Materials Chemistry and Physics, 2008, 107: 110-114

[17] RadwanN. R. E., ElshobakyH. G.. Solid-solid interactions between ferric and cobalt oxides as influenced by Al₂O₃-doping [J]. Thermochimica Acta, 2000, 360: 147-156

[18] WangL.-q., LiuL., XueD.-feng.. Wet routes of high purity BaTiO₃ nanopowders [J]. Journal of Alloys and Compounds, 2007, 440: 78-83

[19] GarciaC. L. A., MontemayorS. M.. Synthesis of CoFe₂O₄ nanoparticles embedded in a silica matrix by the citrate precursor technique [J]. Journal of Magnetism and Magnetic Materials, 2005, 294: e43-e46

[20] RamajoL., CastroM. S., ReboredoM. M.. Effect of silane as coupling agent on the dielectric properties of BaTiO₃-epoxy composites [J]. Composites (Part A): Applied Science and Manufacturing, 2007, 32: 1852-1859

[21] KasapogluN., BaykalA., KoseogluandY.. Microwave-assisted combustion synthesis of CoFe₂O₄ with urea, and its magnetic characterization [J]. Scripta Materialia, 2007, 57: 441-444

[22] ChiuW. S., RadimanS., AbdshukorR., AbdullahM. H., KhiewP. S.. Tunable coercivity of CoFe₂O₄ nanoparticles via thermal annealing treatment [J]. Journal of Alloys and Compounds, 2008, 459: 291-297

[23] StonerE. C., WohlfarthE. P. A.. Mechanism of magnetic hysteresis in heterogeneous alloys [J]. IEEE Transactions on Magnetics, 1991, 27(4): 3475-3518

[24] MaazK., MumtazA., HasansinS. K., CeylanA.. Synthesis and magnetic properties of cobalt ferrite (CoFe₂O₄) nanoparticles prepared by wet chemical route [J]. Journal of Magnetism and Magnetic Materials, 2007, 308: 289-295

[25] ChinnasamyC. N., JeyadevanB., ShinodaK., TohjiK., DjayaprawiraD. J., TakahashiM., JoseyphusR. J., NarayanasamyA.. Unusually high coercivity and critical single-domain size of nearly monodispersed CoFe₂O₄ nanoparticles [J]. Applied Physics Letters, 2003, 83: 2862-2864