Abstract
The most prominent indicator of superconductivity is the superconducting transition temperature (Tc) that refers to three points. The onset transition temperature (Tonset) is defined as the deviation point away from the ρ(T) straight line (onset of the drop in resistivity). The midpoint transition temperature (Tmidpoint) is defined as the temperature, where resistivity becomes 50% of its value at Tonset. The zero-resistance transition temperature (Tρ≈0) is defined as the temperature, in which the resistance is identically zero or only immeasurably small. These indicators of temperatures associated with some factors. In this article, the X-ray diffraction and electrical resistivity measurements of LaO1-xFxFeGe samples are reported. This compound was successfully synthesized via a solid state reaction method with the presence of germanium Ge in the conduction layer. Furthermore, some factors affecting the superconducting transition temperature were studied, which are the F-doping dependence of Tonset, Tmidpoint, and lattice parameters, and sintering temperature dependence of Tonset.
Highlights
Iron-based LnOFeAs phase is not a superconductor and displayed an anomalous change in the slope of ρ(T) resistivity measurement curve
Superconductivity could be obtained from LnOFeAs phase through replacement of O2- with F(i.e., F-doping), with the resulting phase being the LnO1-xFxFeAs compound
All main peaks of the samples can be well determined based on the tetragonal oxypnictide structure LnOMPn, which is indexed to the tetragonal ZrCuSiAs-type structure reported previously (Kamihara et al, 2008, Liang et al, 2007, Hamlin et al, 2008, Kamihara et al, 2006, Che et al, 2008, Chen et al, 2008, Gao et al, 2008)
Summary
Iron-based LnOFeAs phase is not a superconductor and displayed an anomalous change in the slope of ρ(T) resistivity measurement curve. Nickel-based quaternary oxypnictides LaONiP and LaONiAs exhibited superconducting transition in resistivity measurements with critical transition temperature Tonset=4 K (Tρ≈0=2 K) (Watanabe et al 2007, Tegel et al, 2008) and Tonset=2.4 K (Tρ≈0=2 K) (Watanabe et al, 2008), respectively. Superconducting transition temperature Tonset of LaO1-xFxFeAs was at 17 (Dong et al, 2008), 28 (Dong et al, 2008), 24.6 (Gao et al, 2008), and 30 K (Kamihara et al, 2008) for x=0.03, 0.06, 0.10, and 0.11, respectively. The F-doping dependence of Tc and Tonset on LaO1-xFxFeAs (Kamihara et al, 2008), after superconductivity appears, Tc is nearly unchanged up to x=0.14, and the highest Tc=26 K (Tonset= 30 K) is attained at the Fcontent x=0.11
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callMore From: Scientific Journal for the Faculty of Science-Sirte University
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
