NUKLEONIKA 2009, 54(4):227-232



Wiktor Bodnar1, Monika Szklarska-Łukasik1, Paweł Stoch2,3, Piotr Zachariasz3,
Jarosław Pszczoła1, Jan Suwalski3

1 Faculty of Physics and Applied Computer Science, AGH University of Science and Technology,
30 A. Mickiewicza Ave., 30-059 Kraków, Poland

2 Faculty of Material Science and Ceramics, AGH University of Science and Technology,
30 A. Mickiewicza Ave., 30-059 Kraków, Poland

3 Institute of Atomic Energy, 05-400 Otwock-Świerk, Poland

The synthesis of materials, crystal structure and 57Fe Mössbauer effect studies at 77 K were performed for intermetallics Tb0.27Dy0.73(Fe1–xCox)2. The starting compound Tb0.27Dy0.73Fe2 of this Fe/Co substituted series is known as Terfenol-D. XRD measurements evidence a pure cubic Laves phase C15, MgCu2-type. The determined unit cell parameter decreases across the series. Co substitution introduces a local area, in the subnanoscale, with random Fe/Co neighbourhoods of the 57Fe atoms. Mössbauer effect spectra for the Tb0.27Dy0.73(Fe1–xCox)2 series collected at 77 K consist of a number of locally originated subspectra due to random composition of Fe and Co atoms in the nearest neighbourhood. Hyperfine interaction parameters: isomer shift, magnetic hyperfine field and a quadrupole interaction parameter were obtained from the fitting procedure of the spectra, both for the local area and for the sample as bulk. As a result of Fe/Co substitution, a Slater-Pauling type curve for the average magnetic hyperfine field vs. Co content in the
Tb0.27Dy0.73(Fe1–xCox)2 series is observed. It is found that the magnetic hyperfine fields corresponding to the local area sorted out against Co contribution in the Fe/Co neighbourhoods also create a dependence similar to the Slater-Pauling type curve.

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