Neutron diffraction and isotropic volume expansion caused by deuterium absorption into La(Fe0:88Si0:12)13

Shun Fujieda, Asaya Fujita, Kazuaki Fukamichi, Yasuo Yamaguchi, Kenji Ohoyama

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23 Citations (Scopus)

Abstract

The crystal structures and magnetic properties of La(Fe 0:88Si0:12)13D1:5 and La(Fe 0:88Si0:12)13H1:6 have been investigated. The powder neutron diffraction declared that the compound La(Fe0:88Si0:12)13D1:5 has a cubic NaZn13-type structure of the Fm33c space group in analogy with La(Fe0:88Si0:12)13. The deuterium atoms in the compound La(Fe0:88Si0:12)13D1:5 occupy the interstitial 24d site surrounded by two La atoms and four icosahedral clusters. The x-ray diffraction data of La(Fe0:88Si 0:12)13H1:6 are also consistently explained by the same site of hydrogen atom. The deuterium or hydrogen absorption brings out a notable increase of the Curie temperature TC. The neutron diffraction of the compound La(Fe0:88Si0:12) 13D1:5 shows that the magnetic structure is ferromagnetic and the average magnetic moment per Fe is about 2.2 μB, almost the same as that of La(Fe0:88Si0:12)13. Such behaviors can be explained as characteristic magnetovolume effects in itinerant-electron metamagnets. That is, when the hydrogen or deuterium atom at the 24d site causes the isotropic volume expansion, the magnetic free energy curve with a double minimum structure renormalized by spin fluctuations induces a marked increase of TC without a pronounced increase of the magnetic moment.

Original languageEnglish
Article number074722
Journaljournal of the physical society of japan
Volume77
Issue number7
DOIs
Publication statusPublished - 2008 Jul
Externally publishedYes

Keywords

  • Deuterium absorption
  • Hydrogen atom
  • Itinerant-electron metamagnetic transition
  • Magnetic free energy
  • Magnetocaloric effect
  • Magnetovolume effect
  • Powder neutron diffraction
  • Spin fluctuation

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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