Dresden 2003 – scientific programme
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MA: Magnetismus
MA 14: Poster: Schichten(1-31), Spinabh.Trsp.(32-47), Exch.Bias(48-54), Spindyn.(55-64), Mikromag.(65-76), Partikel(77-88), Oflmag.(89-92), Spinelektr.(93-98), Elektr.Theo.(99-103), Mikromag+PhasÜ+Aniso.(104-122), MagnMat.(123-134), Messm+Mol-Mag.(135-139), Kondo(140-151)
MA 14.127: Poster
Tuesday, March 25, 2003, 15:15–19:15, Zelt
Magnetism and electronic structure of DyNi5−xAlx compounds from experiment and theory — •S.G. Chiuzbăian1, E. Burzo2, M. Neumann1, and L. Chioncel3 — 1Universität Osnabrück, Fachbereich Physik, Osnabrück, Germany — 2Faculty of Physics, Babes–Bolyai University, 3400 Cluj–Napoca, Romania — 3Department of Physics, University of Nijmegen, 6500GL Nijmegen, Netherlands
DyNi5−xAlx polycrystalline samples with 0 ≤ x ≤ 3 have been investigated by means of X–ray photoelectron spectroscopy (XPS), magnetic measurements and TB–LMTO band structure calculations [1]. The compounds exhibit a CaCu5–type structure for an aluminium content x ≤ 1.5 and a HoNi2.6Ga2.4–type structure for compositions with x ≥ 2. The saturation moments per formula unit extrapolated at 0 K, are ∼ 9.2 µB in composition range x < 2. For x ≥ 2 a mictomagnetic type contribution to magnetic ordering develops which becomes dominant only for the DyNi2Al3 compound. Band structure calculations show that the Dy 5d band is polarized parallel to the 4f moments while for DyNi5 the nickel moments at 2c and 3g sites are antiparallel oriented to Dy 4f moments. The nickel contributions to the magnetization decrease with increasing aluminium content and are near zero for x ≥ 2. Above the Curie points the reciprocal susceptibilities follows linear dependencies. The effective nickel moments decrease from 2.11 µB/atom (x = 0) to 0.87 µB/atom (x = 2.5). By comparing these data with information arising from XPS spectra, the magnetic behavior of nickel is analyzed in models which take into account the electron correlation effects in d–bands.
[1] E. Burzo et al., J. Applied Physics (2002), accepted for publication