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BY-NC-ND 3.0 license Open Access Published by De Gruyter Open Access February 26, 2011

Symmetry analysis of the behavior of the family R6M23 compounds upon hydrogenation

Agnieszka Kuna and Wiesława Sikora
From the journal Open Physics

Abstract

Symmetry analysis was applied in this work to discuss the behavior of the family R6M23 compounds upon hydrogenation (deuteration), where different structural transformations and magnetic properties, depending on the type of R and M atoms and hydrogen (deuterium) concentrations, have been found. The crystallographic structure of these compounds is described by the Fm3m space group and contain 116 atoms per unit cell occupying the positions 24e(R), 4b, 24d, 32f1 and 32f2(M). Additionally in the elementary cell, there could be up to 100 atoms of hydrogen (or deuterium) occupying the interstitial positions 4a, 32f3, 96j1 and 96k1. The symmetry analysis in the frame of the theory of space groups and their representation gives the opportunity to find all possible transformations from high symmetry parent structure to the structures with symmetry belonging to one of its subgroups. For a given transformation it indicates possible displacements of atoms from initial positions in the parent structure, ordering of hydrogen over interstitial sites and also ordering of magnetic moments, described by the smallest possible number of free parameters. The analysis was carried out by means of the MODY computer program for vectors k = (0; 0; 0) and k = (0; 0; 1) describing the changes of translational symmetry and all positions occupied by the R, M and D atoms.

[1] E. Burzo et al., In: H.P. Wijn (Ed.), Magnetic Properties of Metals: Compounds Between Rare Earth Elements and 3d, 4d or 5d Elements, New Series III/19d2 (Landolt-Börnstein, 1990) 223 Search in Google Scholar

[2] J.J. Rhyne et al., J. Less-Common Met. 94, 95 (1983) http://dx.doi.org/10.1016/0022-5088(83)90145-510.1016/0022-5088(83)90145-5Search in Google Scholar

[3] K. Hardman-Rhyne et al., Phys. Rev. B 29, 416 (1984) http://dx.doi.org/10.1103/PhysRevB.29.41610.1103/PhysRevB.29.416Search in Google Scholar

[4] K. Hardman-Rhyne et al., J. Less-Common Met. 96, 201 (1984) http://dx.doi.org/10.1016/0022-5088(84)90196-610.1016/0022-5088(84)90196-6Search in Google Scholar

[5] N.T. Littewood et al., J. Magn. Magn. Mater. 54–57, 491 (1986) http://dx.doi.org/10.1016/0304-8853(86)90678-510.1016/0304-8853(86)90678-5Search in Google Scholar

[6] Yu. A. Izyumov, V.N. Syromyatnikov, In: Yu. A. Izyumov, V.N. Syromyatnikov (Eds.), Phase Transitions and Crystal Symmetry (Kluwer Academic Publishers, Dordrecht, 1990) 19 http://dx.doi.org/10.1007/978-94-009-1920-4_210.1007/978-94-009-1920-4_2Search in Google Scholar

[7] W. Sikora, F. Białas, L. Pytlik, J. Appl. Crystallogr. 37, 1015 (2004) http://dx.doi.org/10.1107/S002188980402119310.1107/S0021889804021193Search in Google Scholar

[8] G.T. Rado, H. Suhl, In: E.F. Bertaut (Ed.), Treatise on Magnetism, vol. 3 (Academic Press, New York, 1963) Chapter 4 Search in Google Scholar

[9] E.F. Bertaut, J. Phys. 32C1, 462 (1971) 10.1051/jphyscol:19711156Search in Google Scholar

[10] J. Malinowski, PhD thesis, AGH University of Science and Technology (Cracow, Poland, 2007) Search in Google Scholar

[11] O.V. Kovalev, Representations of the Crystallographic Space Groups (Gordon & Breach, London, 1993) Search in Google Scholar

Published Online: 2011-2-26
Published in Print: 2011-6-1

© 2010 Versita Warsaw

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

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