2008/06/26 by G. Wu, G Wu, H. Chen +15
Materials Science · Physics and Astronomy · #Iron-based superconductors research #Magnetic and transport properties of perovskites and related materials #Superconductivity in MgB2 and Alloys #cond-mat.mtrl-sci #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1088/0953-8984/20/42/422201
published as Journal of Physics: Condensed Matter 20, 422201 (2008). · 5 pages, 6 figures
arxiv created 2008/06/26 · openalex publication_date 2008/09/09 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/30
We report intrinsic transport and magnetic properties and their anisotropy in high-quality single-crystal CaFe 2 As 2 . The resistivity anisotropy (ρ c /ρ ab ) is ∼50, less than the 150 of BaFe 2 As 2 , which arises from the strong coupling along the c -axis due to an apparent contraction of about 0.13 nm compared to BaFe 2 As 2 . In sharp contrast to the case of parent compounds ROFeAs (R = rare earth) and MFe 2 As 2 (M = Ba and Sr), spin-density-wave (SDW) ordering (or structural transition) leads to a steep increase of resistivity in CaFe 2 As 2 . Such a different resistivity response to SDW ordering is helpful to understand the role played by SDW ordering in Fe-based high- T c superconductors. The susceptibility behavior is very similar to that observed in single-crystal BaFe 2 As 2 . A linear temperature-dependent susceptibility occurs above the SDW transition of about 165 K. Partial substitution of Na for Ca suppresses the SDW ordering (anomaly in resistivity) and induces superconductivity at ∼20 K.