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Selected Works

Condensed Matter Physics

Frederick S Wells

Publication Year

Articles 1 - 2 of 2

Full-Text Articles in Physics

Vortex-Glass Phase Transition And Enhanced Flux Pinning In C 4+-Irradiated Bafe1.9ni0.1as2 Superconducting Single Crystals, M Shahbazi, X Wang, S Ghorbani, M Ionescu, Olga Shcherbakova, Frederick Wells, Alexey Pan, S Dou, K Choi Dec 2012

Vortex-Glass Phase Transition And Enhanced Flux Pinning In C 4+-Irradiated Bafe1.9ni0.1as2 Superconducting Single Crystals, M Shahbazi, X Wang, S Ghorbani, M Ionescu, Olga Shcherbakova, Frederick Wells, Alexey Pan, S Dou, K Choi

Frederick S Wells

We report the effects of C4+-irradiation on the superconducting properties of BaFe1.9Ni0.1As2 single crystal. The BaFe1.9Ni0.1As2 single crystal before and after C4+-irradiation was characterized by magnetic, magneto-transport and magneto-optical techniques over a wide range of magnetic fields (0-13 T) and temperatures (2-200 K). We demonstrate that the C 4+-irradiation significantly enhances the in-field critical current density (by a factor of up to 1.5 at 5 K) and induces enhanced flux jumping at 2 K, with only a small degradation (by 0.5 K) of the critical temperature, T c. The vortex phase ...


Magneto-Optical Imaging And Current Profiling On Superconductors, Frederick S. Wells Sep 2011

Magneto-Optical Imaging And Current Profiling On Superconductors, Frederick S. Wells

Frederick S Wells

Magneto-optical imaging (MOI) is a useful and highly versatile technique for the investigation of magnetic and current-carrying properties of superconductors. High-speed imaging is particularly important as superconductors often exhibit interesting magnetic behaviour over short timescales, such as the behaviour of individual flux vortices during magnetic flux penetration. The following method was developed to facilitate the high-speed acquisition of magneto-optical images of superconducting samples, and the determination of magnetic field and current flow data from these images. This method may be the first to allow current mapping of short timescale magnetic events in superconductors.
Magneto-optical images were acquired using a high-speed ...