EPL, 86 (2009) 57007
DOI: 10.1209/0295-5075/86/57007

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

chenxh@ustc.edu.cn

received 9 April 2009; accepted in final form 25 May 2009; published June 2009
published online 24 June 2009

Abstract
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.

PACS
74.70.-b - Superconducting materials.
74.25.Ha - Magnetic properties.
74.25.Fy - Transport properties (electric and thermal conductivity, thermoelectric effects, etc.).

© EPLA 2009