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MA: Fachverband Magnetismus

MA 9: Magnetic Particles, Clusters

MA 9.7: Vortrag

Montag, 22. März 2010, 16:45–17:00, H23

NdFeB nanoparticles prepared by wet-milling — •Juliane Thielsch, Julia Lyubina, Thomas Woodcock, Ludwig Schultz, and Oliver Gutfleisch — IFW Dresden, P.O. Box 27 01 16, D-01171 Dresden

Since the prediction of a giant energy product of textured nanocomposite magnets [1] those materials where believed to be the next generation of permanent magnets. For effective exchange-coupling in such two-phase magnets grain sizes need to be in the range of the domain wall width of the hard magnetic phase. That makes a homogenous phase distribution and a microstructure with nanograins necessary. One option of preparing such materials is the synthesis of magnetic nanoparticles which further could be aligned and compacted to a bulk magnet. For this we performed wet-milling experiments of a NdFeGaNbB alloy. XRD studies revealed that by using a surfactant and a solvent during the high energy ball milling process amorphization sets in later than compared to dry milling experiments under the same conditions. Dynamic Light Scattering investigations showed a Gauss distribution of the particle size with a mean diameter of about 12nm which was also proven by TEM. Magnetic properties were measured with SQUID and showed so far rather poor coercivity values.

[1] R. Skomski and J.M.D. Coey, Phys. Rev. B, 1993, 48:15812