| ABSTRACT: |
Small-angle neutron scattering (SANS) measurements of the vortex lattice in single crystal and powder samples of MgB2 - a two band superconductor, are presented. SANS is a powerful method allowing us to measure directly the distribution of vortex separations and hence the anisotropy of the penetration depth, γλ. Single crystal results show the expected rise of γλwith applied field as the weaker, almost isotropic, p-band is suppressed. Results from the powder samples do not show as significant a rise in γλ with field. We believe this originates from 'averaged' properties of the penetration depth experienced by vortices in each multi-crystallite powder grain.
(Reference)
1）Experimental Evidence for Anisotropic Double-Gap Behavior in MgB2, PRL 90 (2003) 157002.
2）Effects of Two-Band Superconductivity on the Flux-Line Lattice in Magnesium Diborid. |
