| Project/Area Number |
17360020
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Thin film/Surface and interfacial physical properties
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| Research Institution | Nagoya University |
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Principal Investigator |
ASANO Hidefumi Nagoya University, Graduate School of Eng, Professor (50262853)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUI Masaaki Toyota Rilcen, Fellow (90013531)
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| Project Period (FY) |
2005 – 2007
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| Project Status |
Completed (Fiscal Year 2007)
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| Budget Amount *help |
¥15,810,000 (Direct Cost: ¥15,000,000、Indirect Cost: ¥810,000)
Fiscal Year 2007: ¥3,510,000 (Direct Cost: ¥2,700,000、Indirect Cost: ¥810,000)
Fiscal Year 2006: ¥4,500,000 (Direct Cost: ¥4,500,000)
Fiscal Year 2005: ¥7,800,000 (Direct Cost: ¥7,800,000)
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| Keywords | Spin Tunneling / Half-Metal / Spin injection / Magnetoresistance Effect / Andreev Reflection / トンネル效果 / 磁気抵抗效果 |
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| Research Abstract |
1. Andreev reflection study by using superconducting junctions combined with XPS analysis has indicated that the intrrfavial spin polarization of La_0.7Sr_0.3MnO_3 (LSMO) films is strongly influenced by detailed interfacial structures such as the existence oldie SrO layer It is demonstrated that the junction method using NbN as a superconducting electrode is a versatile technique for measuring spin polarization of various ferromagnetic matmrialsincluding half-metals
2. By means of LSMO polycrystalline films we have examined and analyzed the underlying mechanism and dominant factors of low field. intergrain magnetoresstance (MB) which originate from the half-metallic grain boundaries of LSMO. The results of LSMO polycrystalline films on Si//Y52/Ba_0.4Sr_0.6Ti_O3 with controlled grain sizes have shown that the intergrain MR is strongly dependent on grain-boundary resistances of polycrystalline films. We have developed the new model that by considering spin dependent scattering as well as
… More
spin dependent tunneling can quantitatively explain the relationship among the intergarin-MR ratio, spin polarization, and grain-boundary resistances.
3. High-quality Sr_2OrReOs (SCRO) films with the long-range order parameter of 0.98 can be grown onto the lattice-matched substrate of SrTiO_3. The syncrotron radiation photoelectron spectroscopy of the interfaces between the SCRO films and various insulating materials has shown that the half-metallic electronic stricture, as evidenced by the multiple-structure of the Re spectra and the valence band spectra, is achieved for the SCRO/MgO interface. High spin polarization of SCRO is also suggested by the properties (TMR ratio of 114% at 42K) of SCRO/MgO/Co junctions.
4. Highly oriented CoMnGe Henslar alloy films and their multilayer devices with MgO barrier can be grown onto Si substrates by the use of Ni'Pa seed and Cr bur layers. Moreover the control of (100) and (111) orientations can be achieved far Hensler alloy films. The study that enables the growth of highly oriented half-metallic Heusler alloy films onto a practically useful substrate of Si, instead of a single crystal MgO subtsrtate, is technologically important in view of their spintronic applications. Less
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