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Synthesis and characterization of two metallic spin-glass phases of Fe Mo4 Ge3

Prior, Timothy; Baker, Peter J.; Battle, Peter D.; Blundell, Stephen J.; Grandjean, Fernande; Lancaster, Tom; Long, Gary J.; Oldham, Sophie E.; Prior, Timothy J.

Authors

Peter J. Baker

Peter D. Battle

Stephen J. Blundell

Fernande Grandjean

Tom Lancaster

Gary J. Long

Sophie E. Oldham



Abstract

Polycrystalline samples of Fe Mo4 Ge3 have been synthesized by the reduction of an oxide mixture at 1248 K and characterized by a combination of diffraction, muon spin relaxation (μ+ SR), Mössbauer spectroscopy, magnetometry, transport, and heat-capacity measurements. The compound adopts a tetragonal W5 Si3 structure (space group I4 mcm); the iron and molybdenum atoms are disordered over two crystallographic sites, 16k and either 4a or 4b. The synthesis conditions determine which fourfold site is selected; occupation of either leads to the presence of one-dimensional chains of transition metals in the structure. In both cases, the electrical resistivity below 200 K is ∼175 μΩ cm. The dc magnetization rapidly rises below 35 K (Fe Mo on 16k and 4b sites) or 16 K (16k and 4a sites), and a magnetization of 1 μB or 0.8 μB per Fe atom is observed in 4 T at 2 K. The ac susceptibility and the heat capacity both suggest that these are glasslike magnetic transitions, although the transition shows a more complex temperature dependence (with two maxima in χ″) when the 4b sites are partially occupied by iron. No long-range magnetic order is thought to be present at 5 K in either structural form; this has been proven by neutron diffraction and μ+ SR for the case when Fe and Mo occupy the 16k and 4b sites. © 2008 The American Physical Society.

Journal Article Type Article
Publication Date Apr 1, 2008
Journal PHYSICAL REVIEW B
Print ISSN 1098-0121
Electronic ISSN 1550-235X
Publisher American Physical Society
Peer Reviewed Peer Reviewed
Volume 77
Issue 13
Pages 134405-1 - 134405-13
APA6 Citation Baker, P. J., Battle, P. D., Blundell, S. J., Grandjean, F., Lancaster, T., Long, G. J., …Prior, T. J. (2008). Synthesis and characterization of two metallic spin-glass phases of Fe Mo4 Ge3. Physical review B: Condensed matter and materials physics, 77(13), 134405-1 - 134405-13. https://doi.org/10.1103/physrevb.77.134405
DOI https://doi.org/10.1103/physrevb.77.134405
Keywords heat-capacity crystal-structure temperature relaxation refinement transition mo5ge3 mo5si3 muons field
Publisher URL https://journals.aps.org/prb/abstract/10.1103/PhysRevB.77.134405
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