Details

Autor(en) / Beteiligte

• Loudon, J C
• Yazdi, S
• Kasama, T
• Zhigadlo, N D
• Karpinski, J

Titel

Measurement of the penetration depth and coherence length of MgB sub(2) in all directions using transmission electron microscopy

Ist Teil von

• Physical review. B, Condensed matter and materials physics, 2015-02, Vol.91 (5)

Erscheinungsjahr

2015

Quelle

PROLA

Beschreibungen/Notizen

• We demonstrate that images of flux vortices in a superconductor taken with a transmission electron microscope can be used to measure the penetration depth and coherence length in all directions at the same temperature and magnetic field. We obtained images of flux vortices from a MgB sub(2) single crystal cut in the ac plane by focused ion beam milling and tilted to 45[degrees] with respect to the electron beam about the crystallographic a axis. A new method was developed to simulate these images that accounted for vortices with a nonzero core in a thin, anisotropic superconductor and a simplex algorithm was used to make a quantitative comparison between the images and simulations to measure the penetration depths and coherence lengths. It was performed on a very small sample, 30 x 15 mu m and 200-nm thick, so this method could prove useful for superconductors where only small single crystals are available, as is the case for some iron-based superconductors.