Regensburg 1998 – wissenschaftliches Programm
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AM: Magnetismus
AM 3: Nanokristalline, hart- und weichmagnetische Materialien
AM 3.4: Vortrag
Montag, 23. März 1998, 16:00–16:15, H23
The relationship between microstructure and hard magnetic properties of nanocomposites Sm2Fe15Ga2Cx with an excess of Fe — •Zhao-hua Cheng1,2, Jun-xian Zhang1,2, Jan van Lier1, Helmut Kronmüller1, and Bao-gen Shen2 — 1Max-Planck-Institut für Metallforschung, Heisenbergstr. 1, 70569 Stuttgart — 2 State Key Laboratory of Magnetism, Institute of Physics, Chinese Academy of Sciences, Beijing 100080, P.R. China
The nanocomposites Sm-Fe-Ga-C with low Sm contents have been prepared directly
by melt-spinning without a subsequent heat-treatment. A highly isotropic
remanence to saturation magnetization ratio of 0.6-0.7 and a relatively high
coercivity of 5.5 kOe were achieved from the as-quenched ribbons. X-ray
diffraction and thermomagnetic analyses show that the as-quenched ribbons
consist of a magnetically hard phase Sm2Fe15Ga2Cx and
a magnetically soft phase
α-Fe. Transmission electron microscopy observation demonstrates that the
major 2:17-type phase has larger crystallites and the crystallites of the minor
phase α-Fe are smaller and located separately at the grain boundaries of
the major phase. The remanence enhancement is attributed to the exchange
coupling between the magnetically hard and soft phases.
Both microstructure and magnetic properties
depend sensitively on the substrate velocity. The effect of the
microstructure on the hard magnetic properties is discussed.
Z.H. Cheng thanks the Alexander von Humboldt Foundation and the National
Natural Sciences Foundation of China for financial
support.