Structure and physical properties of the new layered oxypnictides Sr4Sc2O6M2As2 (M = Fe and Co)Y. L. Xie, R. H. Liu, T. Wu, G. Wu, Y. A. Song, D. Tan, X. F. Wang, H. Chen, J. J. Ying, Y. J. Yan, Q. J. Li and X. H. Chen
Hefei National Laboratory for Physical Science at Microscale and Department of Physics, University of Science and Technology of China - Hefei, Anhui 230026, China
received 9 April 2009; accepted in final form 25 May 2009; published June 2009
published online 24 June 2009
We have successfully prepared the new layered oxypnictides Sr4Sc2O6M2As2 (M = Fe and Co). They adopt the tetragonal structure, being the same as that of Sr4Sc2O6Fe2P2. The lattice constants are a = 0.4045 nm and c = 1.5802 nm for M = Fe and a = 0.4045 nm and c = 1.5695 nm for M = Co, respectively. Their transport and magnetic properties have been systematically studied. The temperature dependence of the Hall coefficient and the thermoelectric power for the Sr4Sc2O6M2As2 compound show a complicated behavior, similar to that of the iron-based parent compounds LnOFeAs and BaFe2As2. This suggests that Sr4Sc2O6Fe2As2 could be considered as a new parent compound of iron-based superconductors.
74.70.-b - Superconducting materials.
74.25.Ha - Magnetic properties.
74.25.Fy - Transport properties (electric and thermal conductivity, thermoelectric effects, etc.).
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