Regensburg 2002 – wissenschaftliches Programm

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MA: Magnetismus

MA 10: Poster : Dünne Schichten(1-21),Spinabh.Transp.(22-39),Exch.Bias(40-51),Spindyn.(52-55),Mikromag.(56-66),Partikel(67-74),Abb.Verf.(75-77),Oberfl.+Spinelektr.+Elektr.Theo+Mikromag(75-87),PÜ+Aniso+Werkst/Leg.(88-103),Mol.Mag.+N-dim+Messm.+Postdead(104-111

MA 10.99: Poster

Dienstag, 12. März 2002, 15:00–19:00, Bereich A

Investigation of magnetism in PrMn_2−xFe_xGe₂ by neutron diffraction — •ILKER DINCER^1,2, YALCIN ELERMAN¹, AYHAN ELMALI¹, HELMUT EHRENBERG², HARTMUT FUESS², and GILLES ANDRE³ — ¹Dept. of Engineering Physics, Faculty of Engineering, Ankara University, 06100 Besevler-Ankara, Turkey — ²Institute for Materials Science, Darmstadt University of Technology, Petersenstr. 23, D-64287 Darmstadt, Germany — ³Laboratoire Leon Brillouin(CEA-CNRS), CEN-Saclay, 91191 Gif-Sur-Yvette, France

The magnetic properties of the PrMn_2−xFe_xGe₂ compounds with ThCr₂Si₂-type structure have been reinvestigated by neutron diffraction[1]. A typical SmMn₂Ge₂-like behaviour is observed for PrMn_1.4Fe_0.6Ge₂. The magnetic structures of PrMn_1.6Fe_0.4Ge₂, PrMn_1.4Fe_0.6Ge₂, PrMn_1.2Fe_0.8Ge₂ and PrMn_1.0Fe_1.0Ge₂ have been determined between 2 and 300 K, and the x-T magnetic phase diagram of this system is proposed. It has been shown that the substitution of Mn by Fe drastically reduces the interlayer ferromagnetic range. These results are compared with NdMn_2−xFe_xGe₂[2] and LaMn_2−xFe_xSi₂[3] in respect to the effect of Fe substitution on the interplane magnetic couplings. The F-AF transition at a critical Mn-Mn interatomic distance R_Mn−Mn^a within the (001) Mn layers(intralayer) is larger than the value (2.865 Å) for pure Mn compounds (e.g. SmMn₂Ge₂). [1] S. Kervan, Y. Elerman, A. Elmali, R. Theissmann, J. Alloys Comp. 327 (2001) 27. [2] G. Venturini, B. Malaman, E. Ressouche, J. Alloys Comp. 237 (1996) 61. [3] I. Dincer, Y. Elerman, A. Elmali, H. Ehrenberg, H. Fuess, in print.