Regensburg 1998 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
AM: Magnetismus
AM 10: Magnetokristalline Anisotropie, Magnetostriktion
AM 10.4: Vortrag
Dienstag, 24. März 1998, 16:00–16:15, H23
A magnetic neutron diffraction study of Nd2Co17−xGax solid solutions — •L. Giovanelli1, H. Kronmüller1, O. Moze2, W. Kockelmann3, and K.H.J. Buschow4 — 1Max-Planck-Institut f"ur Metallforschung, Heisenbergstr. 1, D-70569 Stuttgart — 2Univ. di Modena, Dip. Fisica, Via G. Campi 213/A, I-41100 Modena — 3Rutherford Appleton Laboratory, Chilton, Didcot, OX11 OGX England, United Kingdom — 4Van der Waals-Zeeman Institute, University of Amsterdam, Valckenierstraat 65, 1018 XE, Amsterdam, The Netherlands
An x-ray diffraction study of the substitution of gallium in Nd2Co17
to form the solid solutions Nd2Co17−xGax indicates that
the compounds adopt the rhombohedral Th2Zn17 structure.
The unit-cell volume and the a-axis lattice parameter increase linearly
with increasing x.
Neutron diffraction studies of Nd2Co17−xGax with x=5, 6 and 7
indicate that the gallium completely avoids the 9d site and that the other
sites, 6c, 18f and 18h, are occupied in a non-random manner by gallium atoms.
The magnetic neutron scattering indicates both that the neodymium sublattice
magnetization couples ferromagnetically with the cobalt sublattice and that
there is a change in easy magnetization direction from planar to axial
with increasing gallium concentration. This change in easy magnetization
direction is explained in terms of sign reversal of the second-order
crystal-field parameter, A20 , the most important parameter responsible
for determining the neodymium sublattice anisotropy.