Dresden 2003 – wissenschaftliches Programm

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MA: Magnetismus

MA 14: Poster: Schichten(1-31), Spinabh.Trsp.(32-47), Exch.Bias(48-54), Spindyn.(55-64), Mikromag.(65-76), Partikel(77-88), Oflmag.(89-92), Spinelektr.(93-98), Elektr.Theo.(99-103), Mikromag+PhasÜ+Aniso.(104-122), MagnMat.(123-134), Messm+Mol-Mag.(135-139), Kondo(140-151)

MA 14.125: Poster

Dienstag, 25. März 2003, 15:15–19:15, Zelt

Crystal Growth and Selected Magnetic Properties of Nd₂Fe₁₄B — •Irina Mazilu, Peter Kerschl, Axel Handstein, Karl-Hartmut Müller, Angelika Teresiak, Wolfgang Löser, Günter Behr, and Ludwig Schultz — Leibnitz Institute for Solid State and Materials Research Dresden, Helmholtzstr. 20 ,D-01069 Dresden, Germany

Single crystals of the Nd₂Fe₁₄B compound, which exhibits incongruent melting at 1150 degree Celsius , have been grown by the floating zone technique with optical heating in a Ti-gettered Ar atmosphere. This crucible-free crystal growth method avoids chemical reactions of the melt with crucibles which cause impurities of the Nd₂Fe₁₄B crystals. Because of the large concentration difference between the Nd₂Fe₁₄B crystal and the travelling zone slow growth velocities of 2 mm/h were employed in order to prevent a morphological interface instability by constitutional supercooling.

Nd₂Fe₁₄B crystals of 6 mm in diameter and 40 mm in length were grown. A Laue X-ray back-scattering image exhibits clear reflections of the tetragonal lattice. The crystal axis deviates only 7 degree from the [100] orientation.

The magnetisation curve at 55 K of Nd₂Fe₁₄B with a magnetic field parallel to the [100] orientation was determined on a single-crystal in a high-field pulse up to 25 T. The material exhibits a first-order field-induced magnetisation transition at a field around 17 T. Hysteresis behaviour is visible.