Dresden 2003 – wissenschaftliches Programm

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MA: Magnetismus

MA 3: Magnetische Materialien

MA 3.7: Vortrag

Montag, 24. März 2003, 11:45–12:00, HSZ/401

Magnetic properties of melt spun ribbons of DyMnGeFe₅Al₅ — •Peter Kerschl¹, Bogdan Idzikowski^1,2, Ulrich K. Rößler¹, Konstantin Nenkov¹, Dieter Eckert¹, Karl-Hartmut Müller¹, and Ludwig Schultz¹ — ¹IFW Dresden, Postfach 270116, 01171 Dresden, Germany — ²Inst. Molecular Physics, Polish Academy of Sciences, Poznan, Poland

We have prepared melt-spun ribbons of DyMnGeFe₅Al₅. The main resulting crystallographic structure is akin to DyFe₆Al₆ with a CeMn₄Al₈-type structure (I4/mmm) being itself derived from the ThMn₁₂ structure. Annealing prompts a structural distortion and/or decomposition as found from additional peaks in x-ray pattern. Magnetic measurements in static fields up to 9 T and in the pulsed field device of the IFW Dresden up to 40 T were made. As in the parent compound DyFe₆Al₆ the magnetic order is ferrimagnetic at higher temperature. The ordering temperature of DyMnGeFe₅Al₅ is about 265 K. The magnetic appearance is anomalous with decreasing field-cooled magnetisation towards lower temperatures, due to the interplay of the localised magnetic moment of Dy and the itinerant moment of Fe and Mn with conflicting couplings and anisotropies. Negative remanence values are found after field cooling (µ₀H < 1 T) at T < 60 K. To test this state with negative remanence, fields up to 9 T were applied at 10 K. The resulting remanence is negative, indicating coupling between magnetic sublattices with qualitatively different magnetic anisotropies. This work is supported by BMBF project: 03 SC 5 DRE.