2006/04/21 by V. N. Bogomolov, Bogomolov, V. N.
Chemistry · Physics and Astronomy · #FOS: Physical sciences #Inorganic Fluorides and Related Compounds #Physics of Superconductivity and Magnetism #Quantum, superfluid, helium dynamics #Superconductivity (cond-mat.supr-con) #cond-mat.supr-con
paper · pdf · doi:10.48550/arxiv.cond-mat/0604509
5 pages, 5 figures
arxiv created 2006/04/21 · openalex publication_date 2006/04/21 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
Structures and parameters of some high and low temperature superconductors (HTSC, LTSC) are considered basing on the alternative estimate of the O2- ion radius magnitude (0.5-0.6) A. Phase transitions into the superconducting state are considered as the Bose-Einstein condensation (BEC). The super HTSC with Tc = 371 K (YBa2Cu3Se7) and TC ~ 400K (Ag2(Ag3Pb2H2O6)) and LTSC with Tc~0.3K (SrNbxTi(1-x)O3) are shown to be of the BEC type. Instability of the structure of the first one results from higher magnitude of the Se2- ion radius in comparison with the O2- radius. The second one forms quasi one-dimensional structures and is rather inpractical. The electron density and the effective mass are estimated for some stoichiometric and non-stoichiometric (nano-composite) high temperature superconductors, which have some peculiar features. Large effective masses can indicate existance of polarons (bipolarons) in such systems. Some new superconductors MgxWO3.