Volume 85, Number 1, January 2009
Article Number 17009
Number of page(s) 6
Section Condensed Matter: Electronic Structure, Electrical, Magnetic and Optical Properties
Published online 19 January 2009
EPL, 85 (2009) 17009
DOI: 10.1209/0295-5075/85/17009

A novel non$\hbox{--} $Fermi-liquid state in the iron-pnictide FeCrAs

W. 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 non$\hbox{--} $Fermi-liquid power law, $\rho (T)=\rho _{0}-AT^{x}$ with x < 1, while the specific heat shows Fermi-liquid behaviour with a large Sommerfeld coefficient, $\gamma$ ~ 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 $\rightarrow$ 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.

© EPLA 2009