NUKLEONIKA 2010, 55(3):279-284

 


HYPERFINE INTERACTIONS IN Ho(Fe1-xCox)2 COMPOUNDS AT 295 K



Mikołaj Bednarski1, Paweł Stoch2,3, Wiktor Bodnar1, Piotr Zachariasz2,
Jarosław Pszczoła1, Jan Suwalski2

1 Faculty of Physics and Applied Computer Science, AGH University of Science and Technology,
30 A. Mickiewicza Ave., 30-059 Kraków, Poland
2 Institute of Atomic Energy, 05-400 Otwock-Świerk, Poland
3 Faculty of Material Science and Ceramics, AGH University of Science and Technology,
30 A. Mickiewicza Ave., 30-059 Kraków, Poland

Synthesis of Ho(Fe1–xCox)2 intermetallic compounds, studies of their crystal structure and 57Fe Mössbauer effect analysis were carried out at 295 K. X-ray measurements evidence a pure cubic Fd3m, C15, MgCu2-type Laves phase. The unit cell parameter decreases non-linearly with composition parameter x. Mössbauer effect spectra for the Ho(Fe1–xCox)2 series were composed of a number of locally originated subspectra due to random Fe/Co nearest neighbourhoods. Hyperfine interaction parameters, i.e. isomer shift, the magnetic hyperfine field and a quadrupole interaction parameter were determined from the fitting procedure of the spectra, for both the individual nearest neighbourhoods, and for the sample as bulk. As a consequence of Fe/Co substitution a Slater-Pauling type curve for the average magnetic hyperfine field vs. x is observed. The correlation between the local magnetic hyperfine fields and the average magnetic hyperfine fields is related to weak and strong ferromagnetism of the transition metal sublattice.

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