2012/01/04 by Rongwei Hu, Hu, Rongwei, E. D. Mun +34
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Iron-based superconductors research #Physics of Superconductivity and Magnetism #Rare-earth and actinide compounds #Superconductivity (cond-mat.supr-con) #cond-mat.supr-con
paper · pdf · doi:10.48550/arxiv.1201.0953
30 pages, 15 figures, to be a chapter in the book titled "Iron Pnictide Superconductors: materials, properties and mechanism" by Pan Stanford Publishing
openalex publication_date 2012/01/04 · arxiv created 2012/01/05 · arxiv updated 2012/01/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
In this article we review our studies of the K0.80Fe1.76Se2 superconductor, with an attempt to elucidate the crystal growth details and basic physical properties over a wide range of temperatures and applied magnetic field, including anisotropic magnetic and electrical transport properties, thermodynamic, London penetration depth, magneto-optical imaging and Mossbauer measurements. We find that: (i) Single crystals of similar stoichiometry can be grown both by furnace-cooled and decanted methods; (ii) Single crystalline K0.80Fe1.76Se2 shows moderate anisotropy in both magnetic susceptibility and electrical resistivity and a small modulation of stoichiometry of the crystal, which gives rise to broadened transitions; (iii) The upper critical field, Hc2(T) is ~ 55 T at 2 K for H||c, manifesting a temperature dependent anisotropy that peaks near 3.6 at 27 K and drops to 2.5 by 18 K; (iv) Mossbauer measurements reveal that the iron sublattice in K0.80Fe1.76Se2 clearly exhibits magnetic order, probably of the first order, from well below Tc to its Neel temperature of Tn = 532 +/- 2 K. It is very important to note that, although, at first glance there is an apparent dilemma posed by these data: high Tc superconductivity in a near insulating, large ordered moment material, analysis indicates that the sample may well consist of two phases with the minority superconducting phase (that does not exhibit magnetic order) being finely distributed, but connected with in an antiferromagnetic, poorly conducting, matrix, essentially making a superconducting aerogel.