Journal of the Magnetics Society of Japan
Online ISSN : 1882-2932
Print ISSN : 1882-2924
ISSN-L : 1882-2924
Volume 34, Issue 1
Displaying 1-7 of 7 articles from this issue
Contributed Paper
  • H. Matsushima, H. Gotoh, Y. Takeda, K. Ueda, H. Asano, J. Zhong, A. Ra ...
    2010 Volume 34 Issue 1 Pages 1-4
    Published: January 01, 2010
    Released on J-STAGE: February 12, 2010
    Advance online publication: December 28, 2009
    JOURNAL OPEN ACCESS
      The magnetic and transport properties of bulk polycrystalline samples of double perovskite SrLaVMoO6 have been investigated. Structural analyses have shown that the samples are almost in single phase. Magnetization measurements have indicated that the SrLaVMoO6 compound exhibits a cusp at 125K, which is attributable to an antiferromagnetic transition. Electrical resistivity ρ for the compound showed metallic temperature dependence from 10 to 300 K, with a resistivity ρ value 450 μΩcm at 10 K. A spin polarization P value was measured to be 0.50 using the point-contact Andreev reflection (PCAR) technique. It has been found from X-ray photoemission spectroscopy (XPS) study that SrLaVMoO6 closely resembles the half-metallic Sr2FeMoO6 in the electronic state of the Mo. These results were discussed in term of possible half metallic antiferromagnetism mediated by double-exchange interaction.
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  • T. Tanaka, T. Nishiyama, K. Shikada, M. Ohtake, F. Kirino, M. Futamoto
    2010 Volume 34 Issue 1 Pages 21-29
    Published: January 01, 2010
    Released on J-STAGE: February 12, 2010
    Advance online publication: December 28, 2009
    JOURNAL OPEN ACCESS
      Ni thin films were prepared on MgO(100), MgO(110), and MgO(111) single-crystal substrates in the temperature range between 100 and 500°C by UHV-MBE. The growth process, surface morphology, and magnetic properties were investigated. Ni epitaxial thin films were obtained with different film growth orientations depending on the substrate crystal. When Ni films were deposited on MgO(100) substrates, RHEED reflection from hcp-Ni(1120) crystal was observed. However, X-ray diffraction analysis of the samples indicates that the resulting film structure is fcc-Ni(100), suggesting that the hcp-Ni(1120) is metastable and that most of the film has been transformed into a more stable fcc structure. In contrast, Ni epitaxial thin films with (110)fcc and (111)fcc planes parallel to the substrate surface were obtained on MgO(110) and MgO(111) substrates, respectively. The lattice spacings were almost in agreement with the bulk fcc-Ni values for the Ni films prepared on these MgO substrates. The surface morphology influences the magnetic properties of Ni films grown on MgO substrates.
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  • N. Fukatani, K. Yamaji, C. Shishikura, Y. Takeda, H. Asano, A. Rajanik ...
    2010 Volume 34 Issue 1 Pages 30-33
    Published: January 01, 2010
    Released on J-STAGE: February 12, 2010
    Advance online publication: December 28, 2009
    JOURNAL OPEN ACCESS
      We have investigated the structures, magnetic properties and spin polarization of bulk Fe2CrSi and Fe2Cr1-xVxSi Heusler alloys. Single-phase structures were obtained for all samples by setting the composition 22% forY-atom of X2YZ Heusler alloy. The saturation magnetization of Fe2Cr1-xVxSi for x 0.5 decreased monotonically with increasing V content, while their Curie temperatures Tc and spin polarization P remained constant. For alloys with x > 0.5, saturation magnetization decreased rapidly with increasing V content. Experimental results of spin polarization P were discussed from the viewpoint of the Fe, Cr and V partial density of states determined by the band calculation.
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  • A. Yamamura, S. Honda, J. Inoue, H. Itoh
    2010 Volume 34 Issue 1 Pages 34-38
    Published: January 01, 2010
    Released on J-STAGE: February 12, 2010
    Advance online publication: December 28, 2009
    JOURNAL OPEN ACCESS
      We studied the spin dependence of conductance and magnetoresistance for clean ferromagnet/graphene/ferromagnet junctions by making use of both simple and realistic band models for ferromagnetic leads. We found that conductance decays monotonically with increasing graphene length for pure graphene, but oscillates for doped graphenes. Magnetoresistance had non-zero values when ferromagnetic leads with a realistic band structure were attached. For doped graphene magnetoresistance also oscillates with graphene length. The oscillation period was determined by the Fermi wave length of the doped graphene.
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  • M. Miyatake, N. Kodama
    2010 Volume 34 Issue 1 Pages 39-44
    Published: January 01, 2010
    Released on J-STAGE: February 12, 2010
    Advance online publication: December 28, 2009
    JOURNAL OPEN ACCESS
      The risk of electrical discharge between the head and disk in a Hard Disk Drive (HDD) system is discussed. Discharge can cause GMR/TMR element to degrade and/or damage the disk, which would result in quality degradation. Within this paper, the root cause and the mechanism of such discharge and HDD design concept are discussed to avoid the issue. More specifically, our study shows that the voltage difference between head and disk should be within +1∼-1 volt range and it indicates that discharge issue is not parts oriented, but rather must be resolved by balancing the electrical charge of the whole HDD system.
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  • R. Arai, S. Inui, Y. Ohira
    2010 Volume 34 Issue 1 Pages 45-48
    Published: January 01, 2010
    Released on J-STAGE: February 12, 2010
    Advance online publication: December 28, 2009
    JOURNAL OPEN ACCESS
      This paper discusses our examination into a decrease in detent force to improve the positioning accuracy of an X-Y linear synchronous motor (X-Y LSM). The finite element method was used to analyze detent force and static thrust. The detent force was decreased by changing the distance between the mover magnet centers of the X-Y LSM. The following characteristics were examined: (1) detent force associated with the distance between the mover magnet centers, and (2) static thrust associated with the distance between the mover magnet centers.
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  • T. Nishiyama, K. Shikada, M. Ohtake, F. Kirino, M. Futamoto
    2010 Volume 34 Issue 1 Pages 5-20
    Published: January 01, 2010
    Released on J-STAGE: February 12, 2010
    Advance online publication: December 28, 2009
    JOURNAL OPEN ACCESS
      FeCo thin films were prepared on SrTiO3(100), SrTiO3(110), and SrTiO3(111) single-crystal substrates by ultra-high vacuum molecular beam epitaxy. The film growth structure and magnetic properties were investigated. FeCo epitaxial thin films are obtained on these SrTiO3 substrates at elevated temperatures with different crystal growth orientations. The nucleation and growth process of FeCo thin films on SrTiO3 substrates vary depending on the orientation of the substrate and its temperature. FeCo(100) single-crystal thin films with an A2 structure are obtained on SrTiO3(100) substrates at 500°C. FeCo epitaxial thin films with (110)A2 and (211)A2 planes parallel to the substrate surface are obtained on SrTiO3(110) substrates. FeCo thin films epitaxially grown on SrTiO3(111) substrates consist of two crystallographic phases having A2 and hexagonal structures with the (110)A2 and (0001)hex planes parallel to the substrate surface. The metastable FeCo(0001)hex plane is presumably formed in order to relax the strain caused by the lattice mismatch at the FeCo/SrTiO3(111) interface. The lattice constants of Fe50Co50 crystal with the hexagonal structure are estimated to be a = 0.251±0.004 nm and c = 0.457±0.005 nm. The magnetic properties of FeCo epitaxial thin films grown on SrTiO3 substrates are influenced by the magnetocrystalline anisotropy and shape anisotropy caused by the roughness of FeCo islands that form the FeCo thin films.
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