Regensburg 1998 – wissenschaftliches Programm

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AM: Magnetismus

AM 3: Nanokristalline, hart- und weichmagnetische Materialien

AM 3.1: Hauptvortrag

Montag, 23. März 1998, 14:30–15:15, H23

Magnetic properties and spin disorder in nanocrystalline materials — •A. Hernando — Instituto de Magnetismo Aplicado, RENFE -UCM-CSIC, P.O. Box 155, Las Rozas, E -28230 Madrid, Spain

Some characteristics of the magnetic properties of the interfaces can be observed macroscopically in nanocrystalline materials in which the volume fraction of the interfaces becomes relevant. The behaviour of three samples is analysed and correlated to the nanostructure. First, nanocrystalline Fe obtained by ball milling, second, nanocrystalline FeRh obtained by the same procedure and finally, nanocrystalline Co immersed in an amorphous CoB matrix, obtained by devitrification of the melt spun amorphous alloy Co₈₀B₂₀. Magnetic measurements, M"ossbauer spectroscopy, X-ray diffraction and TEM have been used as experimental techniques. Spin disorder at the interfaces is clearly observed in Fe and FeRh nanocrystals. The influence of the Co nanograins on the magnetic properties of the amorphous CoB has been also analysed and correlated to the structural observations carried out by high resolution electron microscopy.