A novel nonFermi-liquid state in the iron-pnictide FeCrAsW. Wu1, A. McCollam1, I. Swainson2, P. M. C. Rourke1, D. G. Rancourt3 and S. R. Julian1
1 Department of Physics, University of Toronto - 60 St. George Street, Toronto, Ontario, Canada M5S 1A7
2 Canadian Neutron Beam Centre, National Research Council Canada - Building 459, Chalk River Laboratories, Chalk River, Ontario, Canada K0J IJ0
3 Department of Physics, University of Ottawa - Ottawa, Ontario, Canada K1N 6N5
received 3 November 2008; accepted in final form 7 December 2008; published January 2009
published online 19 January 2009
We report transport and thermodynamic properties of stoichiometric single crystals of the hexagonal iron-pnictide FeCrAs. The in-plane resistivity shows an unusual “non-metallic" dependence on temperature T, rising continuously with decreasing T from ~ 800 K to below 100 mK. The c-axis resistivity is similar, except for a sharp drop upon entry into an antiferromagnetic state at TN ~ 125 K. Below 10 K the resistivity follows a nonFermi-liquid power law, with x < 1, while the specific heat shows Fermi-liquid behaviour with a large Sommerfeld coefficient, ~ 30 mJ/mol K2. The high-temperature properties are reminiscent of those of the parent compounds of the new layered iron-pnictide superconductors, however the T 0 K properties suggest a new class of non-Fermi liquid.
71.10.Hf - Non-Fermi-liquid ground states, electron phase diagrams and phase tansitions in model systems.
72.15.Qm - Scattering mechanisms and Kondo effect.
72.80.Ga - Transition-metal compounds.
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