Regensburg 2002 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
M: Metallphysik
M 12: Amorphe und metastabile Metalle III
M 12.5: Fachvortrag
Dienstag, 12. März 2002, 15:30–15:45, H4
Microstructure and magnetic properties of the inhomogeneous glass-forming alloy Nd60 Fe30 Al10 — •Alberto Bracchi1, Michael Seibt2, Susanne Schneider1, and Konrad Samwer1 — 1I. Physikalisches Institut, Universität Göttingen, Bunsenstr. 9, D-37073 Göttingen — 2IV. Physikalisches Institut, Universität Göttingen, Bunsenstr. 13-15, D-37073 Göttingen
Thin foils of nominal composition Nd60 Fe30 Al10 with a thickness of about 30 µm, prepared by splat-quenching, have been studied by analytical electron microscopy, small angle neutron scattering (SANS) and with the use of a vibrating sample magnetometer. These investigations show the existence of an in-situ formed Nd-rich nanocrystalline phase embedded into a Fe-rich matrix and forming an extend network over the whole sample. The observed microstructure might be related to phase separation in the undercooled liquid and most likely it explains the hard magnetic behaviour shown by the sample. The SANS data of the as-prepared sample exhibits a power law behaviour with an exponent of -2.3, indicating a mass fractal whose volume fraction is small compared to a compact phase. Low temperature magnetic measurements show a hysteresis loop characterised by a two-phase behaviour probably due to the different magnetic properties (coercive field and magnetisation) of the Nd-rich structure and of the residual matrix. After annealing (below the glass transition temperature and in the glass transition region) the SANS data show a higher exponent of the power law behaviour (respectively -2.5 and -2.8) expressing an evolution of the mass-fractal microstructure towards a bulk microstructure.