[Zurück]

M. El-Hagary, H. Michor, S. Özcan, M. Giovannini, A. Matar, Z. Heiba, P. Kerschl, M. Schönhart, E. Bauer, R. Grössinger, G. Hilscher, J. Freudenberger, H. Rosner:
"Phase formation and ferrimagnetism of GdCo₉Si₄";
Journal of Physics: Condensed Matter, 18 (2006), S. 4567 - 4580.

Phase formation and ferrimagnetism of GdCo₉Si₄

M El-Hagary et al 2006 J. Phys.: Condens. Matter 18 4567-4580 doi:10.1088/0953-8984/18/19/011

M El-Hagary 1,2, H Michor 1,8, S Özcan 1, M Giovannini 3, A Matar 4, Z Heiba 5, P Kerschl 1, M Schönhart 1, E Bauer 1, R Grössinger 1, G Hilscher 1, J Freudenberger 6 and H Rosner 7

1 Institut für Festkörperphysik, Technische Universität Wien, Wiedner Hauptstrasse 8-10, A-1040 Wien, Austria
2 College of Science, Physics Department, Qassim University, Buraidah 81999, Kingdom of Saudi Arabia
3 Dipartimento di Chimica e Chimica Industriale, Università di Genova, Via Dodecaneso 31, I-16146 Genova, Italy
4 Physics Department, Faculty of Science, Helwan University, Helwan, Cairo, Egypt
5 Physics Department, Faculty of Science, Ain Shams University, Cairo, Egypt
6 Leibniz-Institut für Festköper- und Werkstoffforschung, IFW Dresden, D-01171 Dresden, Germany
7 Max-Planck Institut für Chemische Physik fester Stoffe, Nöthnitzer Strasse 40, D-01187 Dresden, Germany
8 Author to whom any correspondence should be addressed
E-mail: michor@ifp.tuwien.ac.at

Abstract.
The phase relations of the GdCo_13-xSi_x system have been studied by means of scanning microscopy, microprobe analysis and x-ray diffraction. Single-phase samples GdCo_9+-δ Si_4-+δ (structure type LaFe₉Si₄ with space group I4/mcm) are formed in a narrow composition range |δ| <= 0.2, where GdCo₉Si₄forms as a fully ordered ternary compound. The magnetic properties of GdCo₉Si₄ have been investigated by ac susceptibility, magnetization, specific heat and resistivity measurements. These experiments reveal ferrimagnetism below about 47 K, which is analysed in terms of a two-sublattice molecular field model with a local moment Gd subsystem coupling antiparallel to the itinerant ferromagnetic Co 3d sublattice. The 3d-3d exchange of the latter is the driving force for the onset of long range magnetic order. The validity of the two-sublattice model is demonstrated by high field measurements, showing that the ferrimagnetic coupling starts to break up at a lower critical field μ₀H₁~= 27 T. The magnetic ground state of GdCo₉Si₄ has been analysed on a microscopic basis via LSDA electronic structure calculations.

Print publication: Issue 19 (17 May 2006)
Received 12 January 2006
Published 26 April 2006

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http://aleph.ub.tuwien.ac.at/F?base=tuw01&func=find-c&ccl_term=AC05938242

http://www.iop.org/EJ/abstract/0953-8984/18/19/011/