• Title/Summary/Keyword: 비탄성 중성자 산란

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Introduction to Neutron Scattering for Magnetic Materials Research (자성소재 연구를 위한 중성자산란 입문)

  • Jeong, Jae-Hong;Lee, Sang-Hyun;Park, Je-Geun
    • Journal of the Korean Magnetics Society
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    • v.22 no.3
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    • pp.103-108
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    • 2012
  • Having a de Broglie wavelength of a few ${\AA}$ with its corresponding energies in the range of a few to a few hundreds meV, neutrons are ideally suited for the studies of structure and dynamics in condensed matter research. Neutron scattering has been developed over the past 60 years or so and become a very mature and established experimental technique in the very broad range of material sciences. In this short introductory article, we have explained its working principles and provided few selected examples of application.

New Magnetic Phases of Fe-N and Mn-Al Alloys Produced by Mechanochemical Milling (기계적 밀링 및 화학적 추출법에 의해 제조한 Fe-N 및 Mn-Al계의 새로운 자성재료)

  • Kyu-Jin Kim;Tae-Hwan Noh;Kenji Suzuki
    • Journal of the Korean Magnetics Society
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    • v.4 no.4
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    • pp.347-354
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    • 1994
  • The structural change and magnetic properties of mechanically milled Fe-N and Mn-Al alloy powders have been investigated by XRD, TEM, VSM, $M\"{o}ssbauer$ spectroscopy and inelastic neutron scattering measurements. During milling of ${\gamma}'-Fe_{4}N$ powders, and fcc ${\gamma}'-Fe_{4}N$ phase is transformed to a bct ${\alpha}'-Fe(N)$ phase by stress-induced martensitic transformation, being accompanied by an initial increase in saturation magnetization. During annealing the bct ${\alpha}'-Fe(N)$ nanocrystalline phase which is obtained by mechanical grinding for a long time, an ${\alpha}'-Fe_{16}N_{2}$ phase partially appears as an intermediate phase at 673~773 K, causing an increase in saturation magnetization. During milling of Mn-45, 70 and 85 at.% Al mixed powders, Al atoms are partially solubilized into an ${\alpha}-Mn$ phase. The Al supersaturated ${\alpha}-Mn-type$ phases change from paramagnetic to ferromagnetic : the saturation magnetization is 11 emu/g for the as-milled Mn-70 at.% Al powders. Moreover, by removing almost all Al atoms from the as-milled Mn-85 at.% Al powders using chemical leaching, the saturation magnetization increases up to 36 emu/g. The above bct ${\alpha}'-Fe(N)$ and ferromagnetic ${\alpha}-Mn$ type alloys are the magnetic materials found for the first time, by using the present mechanochemical process.

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