Edge dislocation and superstructure in MgB2 superconducting crystals
Authors: Du, Wei; Zhang, Hongbin; Xu, Dong; Wang, Xinqiang; Hou, Xianqin; Zhang, Guanghui; Geng, Yanling; Liu, Heyi; Jiang, Fuyi; Wang, Yanling
Source: Superconductor Science and Technology, Volume 18, Number 11, November 2005 , pp. 1513-1516(4)
Publisher: IOP Publishing
Abstract:Hexagonal plate-shaped MgB2 crystals have been prepared at ambient pressure. A superconducting transition has been observed at 37 K with a large transition width of ΔTc~22 K. The lattice strain (0.7%) is calculated from the FWHM of XRD data. Both an edge dislocation with Burgers vector b = -a, and a Mg (nano-agglomerate) self-ordering superstructure with lattice constant 2a0 have been directly detected in the  direction by HRTEM. The very broad transition may be caused by these defects in the crystals.
Document Type: Research Article
Publication date: November 1, 2005