Research

Fig.1. TRMOI images from a six-filament YBCO thin film for different phase points of the applied ac with I0=8 A. A dc magnetic field of 5 mT is applied perpendicular to the film. The arrow indicates the current direction.

We study the current and field distributions in different types of multifilament (YBCO thin film) geometries subjected to the simultaneous application of external magnetic field and AC current by TRMOI technique and by numerical simulation using COMSOL software. It was observed that the field and current dynamics in multifilamentary sample depends on the filament spacing, due to magnetic coupling between the filaments. An increase in distance between the filaments resulted in evenly redistribution of screening and transport current and a reduction of AC losses.

Fig.2. The magnetic field distribution in the multifilament sample, The positive-to-negative ac cycles are colored in red-black-blue shades. 

References:

1. A. Lucarelli, R. Yang, F. Grilli, T. Haugan, P. Barnes, and G. Lüpke, Dynamic Field and Current Distributions in Multifilamentary YBa2Cu3O7-δ  Thin Films with Magnetic Coupling, Journal of Applied Physics 106, 063904 (2009).

2. A. Lucarelli, F. Grilli, G. Lüpke, T. J. Haugan, and P. N. Barnes, Finite-Element Simulations of Field and Current Distributions in Multifilamentary Superconducting Films, Supercond. Sci. Technol. 22, 105015 (2009).

Funding: DOE