| Project/Area Number |
05453079
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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 |
Inorganic materials/Physical properties
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| Research Institution | Okayama University |
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Principal Investigator |
MIURA Yoshinari Okayama Univ., Faculty of Environ.Sci.& Tech.Prof., 環境理工学部, 教授 (80032952)
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| Co-Investigator(Kenkyū-buntansha) |
FUJII Tatsuo Okayama Univ., Faculty of Eng., Lecture, 工学部, 講師 (10222259)
OSAKA Akiyoshi Okayama Univ., Faculty of Eng., Prof., 工学部, 教授 (20033409)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥7,100,000 (Direct Cost: ¥7,100,000)
Fiscal Year 1994: ¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1993: ¥5,300,000 (Direct Cost: ¥5,300,000)
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| Keywords | artifical superlattice / Fe_3O_4 / MgO film / activated reactive evaporation / CoO film / titanium oxidefilm / 酸化チタン |
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| Research Abstract |
Magnetic superlattices including ferromagnetic and diamagnetic layrs bring interesting properties such as the giant magnetoresistance and the mangneto-optical effects. On the other hand, it is well known that titanium oxides change their properties sensitively with their metal to oxygen ratios.
Fe_3O_4/Mo (M=Mg, Co) superlattice films having various thickness combinations of the individual Fe_3O_4 and Mo were prepared by an activated reactive evaporation (ARE) method. Stoichiometric and monstoichiometric titanium oxide films were also epitaxially formed on alpha-Al_2O_3 (0001) substrates by ARE method. The summarized results are as follows :
1. Epitaxial growths and artificial modulations of (111) -and (100) -orientated Fe_3O_4/Mgo films deposited on (0001) -faced alpha-Al_2O_3 and (100) -faced Mgo single crystaline substrates, respectively, were confirmed. The saturation magnetization of each film at 5K was about 85-100 emu/g, being nealy consistent with that of the Fe_3O_4 bulk. However, with increasing temperature the magnetizations decreased linearly in proportion to 1/T below 40K.
2. For Fe_3O_4/CoO film the lattice spacing along the growth direction was contracted for the CoO layr but expanded for the Fe_3O_4 layr probably due to the lattice mismatch between these layrs. The magnetostriction of CoO layrs induced in-plane and perpendicular magnetic anisotropy in (100) -and (111) -oriented superlattices, respectively. Strong magnetic coupling between Fe_3O_4 and CoO layrs made the Neel temperature of the CoO layr higher and showed the ferrimagnetic/antiferromagnetic exchange anisotropy.
3. Titanium di-and sesquioxide films were epitaxially grown on (0001) alpha-Al_2O_3. Films prepared at Po_2*2.0*10^<-4> Torr were stoichiometric (100) -oriented rutile of TiO_2. AtP_<02>=0.6*10^<-4> Torr, on the other hand, (001) -oriented Ti_2O_3 was formed and an electrical transition was clearly detected at about 400K.
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