2007/04/30 by Huan Yang, Ying Jia, Lei Shan +8 · 25 citations
Materials Science · Physics and Astronomy · #Condensed matter physics #Geometry #Iron-based superconductors research #Physics #Physics of Superconductivity and Magnetism #Scaling #Superconductivity in MgB2 and Alloys #Thermodynamics #Vortex #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevb.76.134513
published in Physical Review B 76(13) (American Physical Society) · 7 pages, 9 figures
openalex publication_date 2007/10/22 · arxiv created 2007/10/30 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The current-voltage (I\text\ensuremath-V) characteristics of various MgB2 films have been studied at different magnetic fields parallel to the c axis. At fields \ensuremathμ0H between 0 and 5\phantom\rule0.3em0exT, vortex liquid-glass transitions were found in the I\text\ensuremath-V isotherms. Consistently, the I\text\ensuremath-V curves measured at different temperatures show a scaling behavior in the framework of quasi-two-dimension (quasi-2D) vortex-glass theory. However, at \ensuremathμ0H\ensuremath\geqslant5\phantom\rule0.3em0exT, a finite dissipation was observed down to the lowest temperature here, T=1.7\phantom\rule0.3em0exK, and the I\text\ensuremath-V isotherms did not scale in terms of any known scaling law, of any dimensionality. We suggest that this may be caused by a mixture of \ensuremathσ band vortices and \ensuremathπ band quasiparticles. Interestingly, the I\text\ensuremath-V curves at zero magnetic field can still be scaled according to the quasi-2D vortex-glass formalism, indicating an equivalent effect of self-field due to persistent current and applied magnetic field.