| Project/Area Number |
62550470
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Physical properties of metals
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| Research Institution | TOHOKU UNIVERSITY |
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Principal Investigator |
NAKAJIMA Hideo Institute for Materials Research, Tohoku University, 金属材料研究所, 助教授 (30134042)
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| Co-Investigator(Kenkyū-buntansha) |
YAMAGUCHI Sadae Institute for Materials Research, Tohoku University, 金属材料研究所, 教授 (80005892)
KOIWA Masahiro Department of Metal Science and Technology, Kyoto University, 工学部, 教授 (00005860)
FUJIMORI Hiroyasu Institute for Materials Research, Tohoku University, 金属材料研究所, 教授 (60005866)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1988: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1987: ¥1,600,000 (Direct Cost: ¥1,600,000)
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| Keywords | multilayer thin films / molybdenum / superlattice / amorphous / interdiffusion / superconductivity / 多相膜 / 超伝導 / 臨界磁場 / 構造緩和 |
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| Research Abstract |
Multilayerd Mo/Si thin films have been prepared by a dual rf-magnetron sputtering technique. X-ray diffractometry shows that for the modulation wavelength 【.Ibdabar.】 shorter than 3 nm both Mo and Si sublayers are amorphous, while for 【.Ibdabar.】 longer than 3 nm, crystalline bcc structure appears in Mo sublayers. Interdiffusion in Mo/Si and MoN/SiN multilayer thin films has been studied by X-ray diffraction over the annealing temperature range from 674 to 1027K. The interdiffusivities have been determined from the decay rate of satellite peak intensity around (000). The temperature dependence of the interdiffusivities in Mo/Si and MoN/SiN multilayer films is expressed as D<@D4-@>D4(Mo/Si) = 2.0x10<@D1-16@>D1exp(-105 5 kJmol<@D1-1@>D1/RT) m<@D12@>D1s<@D1-1@>D1, D<@D4-@>D4(MoN/SiN) = 1.6x10<@D1-5@>D1exp(-351 88 kJmol<@D1-1@>D1/RT) m<@D12@>D1s<@D1-1@>D1.
The large reduction in the modulation wavelength is observed in the annealed Mo/Si multilayer films. This behaviour is discussed in connection with the stuctural change. The superconducting transition temperature Tc and the upper critical field Hc<@D22@>D2 have been examined by resistance measurements. The 【.Ibdabar.】 dependence of Tc shows that the multilayer films with equal thichness of Mo and Si are superconducting with the maximum Tc, 6.1 K for 【.Ibdabar.】 =2.3 nm. The superconductivity of the multilayers has been confirmed to result from amorphous MoSi phase formed in the interfacial region of the sublayers. The thichness of the superconducting amorphous layer is estimated to be about 3 nm from the 【.Ibdabar.】 dependence of Tc and from the result of the anisotropy of Hc<@D22@>D2. Keeping the Mo sublayer thickness less than 2.4 nm to suppress the appearance of the crystalline Mo and increasing the Si sublayer thickness, an ideal quasi-two dimensional superconductor with with dHc<@D22@>D2 /dT as high as 180 kOe/K has been realized.
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