2003/07/16 by L. Lyard, P. Szabó, P. Szabo +8
Materials Science · Physics and Astronomy · #Iron-based superconductors research #Physics of Superconductivity and Magnetism #Superconductivity in MgB2 and Alloys #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevlett.92.057001
4 pages, 4 figures
arxiv created 2003/07/16 · openalex publication_date 2004/02/02 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
The temperature dependence of the upper (Hc2) and lower (Hc1) critical fields has been deduced from Hall probe magnetization measurements of high quality MgB2 single crystals along the two main crystallographic directions. We show that \ensuremathΓ_Hc2=H_c2\ensuremath∥ab/H_c2\ensuremath∥c and \ensuremathΓ_Hc1=H_c1\ensuremath∥c/H_c1\ensuremath∥ab differ significantly at low temperature (being \ensuremath∼5 and \ensuremath∼1, respectively) and have opposite temperature dependencies. We suggest that MgB2 can be described by a single field dependent anisotropy parameter \ensuremathγ(H) (=\ensuremathλc/\ensuremathλab=\ensuremathξab/\ensuremathξc) that increases from \ensuremathΓ_Hc1 at low field to \ensuremathΓ_Hc2 at high field.