Vortex Pinning in the High-Tc Superconductor YBa2Cu3O6+x
Final performance rept. 15 May 2005-31 Dec 2008
HARVARD UNIV CAMBRIDGE MA DEPT OF PHYSICS
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This report documents the design and construction of a low temperature scanning tunneling microscope optimized for the study of superconductors. The microscope was first used to study the vortex liquid state in the cuprate high-Tc superconductor Bi2Sr2Cu06x. This work distinguished between a homogenous superconducting gap and an additional inhomogenous pseudogap which may be linked to an alternative electronic ordered state. The microscope then performed the first atomic resolution, high-field investigation of the new iron arsenic high-Tc superconductors. In particular, the vortex state was mapped in BaCoxFe1-x2As2. Vortices formed a disordered lattice, uncorrelated with surface impurities, which demonstrated strong bulk pinning. Vortex core states were used to measure an electronic correlation length of 2.8 nanometers, from which an upper critical field of 43 Tesla was calculated.
- Electricity and Magnetism
- Atomic and Molecular Physics and Spectroscopy