1990 Fiscal Year Final Research Report Summary
Study on Electronic Ceramic Materials Synthesized by Sol-Gel Method
| Project/Area Number |
63460118
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
電子材料工学
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| Research Institution | Toyohashi University of Technology |
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Principal Investigator |
FUJII Toshitaka Toyohashi University of Technology, Dept. of Electr. and Electronic Engng. Professor, 工学部, 教授 (90023168)
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| Co-Investigator(Kenkyū-buntansha) |
UENO Akifumi Toyohashi University of Technology, Dept. of Materials Science Professor, 工学部, 教授 (30135420)
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| Project Period (FY) |
1988 – 1990
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| Keywords | Sol-gel method / mist-pyrolysis / ferromagnetic iron oxides / ceramic fine particles / magnetic thin films / amorphous films / magneto-optical media / Mossbauer spectroscopy |
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| Research Abstract |
1. Preparation of iron-based-oxide powders by sol-gel method using nitrates of constituent metal ions dissolved in ethylene glycol.
(1) Maghemite (gamma-Fe_2O_3) powders are synthesized at temperatures below 300 ^ﾟC.
(2) Addition of boron, phosphor or sodium in maghemite is effective for improvement in thermal stability as well as magnetic properties of maghemite. Ultrafine maghemite particles with the grain diameter less than 10nm retaining large magnetic moment. are obtained by the addition of boron at the borronnocentration B/(Fe+B)=0.2.
(3) Crystallographic single phase yttrium iron garnet (YIG) and bismuth substituted YIG powders are synthesized by gel processing and mist-pyrolysis. The amount of bismuth substitution is increased by citrate gel processing.
2. Preparation of iron-based-oxide thin films by gel-coating on flat substrates.
(1) Transparent films with a considerably large magnetization of 4piM_2 =3.1kG were obtained for the Fe-B-O system with B/(Fe +B)=0.2.
(2) Polycrystallin
… More
e YIG and Bi-substituted YIG films were prepared by spin-coating the gel on glass substrates. Perpendicularly magnetized films were obtained by substituting partly aluminum for iron. Magneto-optical Faraday rotation is enhanced in multicoated films by presumably multireflection of interfaces formed by the gel-coating.
(3) Single crystal YIG and Bi-substituted YIG films were grown by gel-coating on single crystal (GdCa)_3(GaMgZn)_5O_<12> substrates at a temperature of 580 ^ﾟC. It is considered that crystal growth proceeds from low temperature liquid phase epitaxy. The amount of bismuth substitution is greatly increased up to 2.5 in the formula unit.
(4) Amorphous ferromagnetic oxide films with the Bi_2O_3-Fe_2O_3-PbTiO_3 system were prepared by gel-coating on glass plates, since this system films prepared by rf-reactive sputtering are found to exhibit ferromagnetism and ferroelectricity simultaneously well above room temperature. The magnetic properties of gel-coated films resemble those of sputtered films. Investigation is now progressing.
3. Development of magneto-optical (MO-) materials composed of fine ferromagnetic particles. MO-media with discrete structure utilizing fine ferromagnetic particles dispersed in a liquid were investigated. We tentatively used magnetic inks of Ba-ferrite, magnetic fluids of magnetite and cobalt suspensions for magnetic particles, and polyvinyl alcohol and styrene monomer for resins. Transparent materials which exhibit magnetic as well as optical uniaxial anisotropies can be prepared by applying a magnetic field during solidification of the resin. MO-properties of these materials are now in progress. Less
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