Autori: Liang L. Zhao, Tanghong Yi, James C. Fettinger, Susan M. Kauzlarich andE. Morosan

Editorial: Physical Review B (R) - Editor's suggestion, 80, p.020404, 2009.

Rezumat:

The recently discovered CaFe4As3 system displays low-temperature Fermi-liquid behavior, with enhanced electron-electron correlations. At high temperatures, the magnetic susceptibility shows Curie-Weiss behavior, with a large temperature-independent contribution. Antiferromagnetic ordering is observed below TN=(88.0±1.0)K, possibly via a spin density wave transition. A remarkably sharp drop in resistivity occurs below T2=(26.4±1.0) K, correlated with a similarly abrupt increase in the susceptibility but no visible feature in the specific heat. The electronic specific-heat coefficient gamma at low temperatures is close to 0.02mJ/molFeK2, but a higher value for gamma ~0.08mJ/molFeK2 can be inferred from a linear Cp/T vs T2 just above T2. The Kadowaki-Woods ratio A~55*10-5 microOhm cm mol2 K2 mJ-2 is nearly two orders of magnitude larger than that of heavy fermions.

Cuvinte cheie: iron pnictides, spin density wave