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 language | English |
---|---|
Article number | 074722 |
Journal | journal of the physical society of japan |
Volume | 77 |
Issue number | 7 |
DOIs | |
Publication status | Published - 2008 Jul |
Externally published | Yes |
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)