Magneto-optical images of Ag/Bi-2223 tapes processed by flat rolling, "sandwich" rolling and pressing

Dynamic magneto-optical imaging of superconducting thin films

“…This technique shows visually the position of cracks [5,8], weak links [4,6,7] and other micro-and macroscopic defects in the sample [2,9], however there may be other current-limiting mechanisms that are not so readily visible at the macroscopic scale nor directly dependent on critical current density [10,11].…”

“…Magneto-Optical imaging of superconducting samples has proven extremely useful for quality assurance purposes, with the ability to quickly analyse the quality of films [1][2][3][4] and tapes [1,[5][6][7][8] in a non-contact, nondestructive and simple way. This technique shows visually the position of cracks [5,8], weak links [4,6,7] and other micro-and macroscopic defects in the sample [2,9], however there may be other current-limiting mechanisms that are not so readily visible at the macroscopic scale nor directly dependent on critical current density [10,11].…”

Quantitative analysis of current density distributions from magneto-optical images of superconducting YBa2Cu3O7 thin films

“…Magneto-optical imaging (MOI) is a useful tool for imaging the magnetic field associated properties of various materials [1,2]. MOI has been applied to superconducting samples in small fields, providing visual information about the magnetic flux distribution, flux dynamics in bulk conductors [3,4], flux penetration into irradiated conductors [5], and flux penetration within filaments of powder in tube conductors [6] and along networks of grain boundaries in thin film superconducting tapes, deposited on crystalline substrates with various composite layers (coated conductors) [7][8][9][10][11][12][13][14][15][16][17]. The MOI technique has also been employed to experimentally determine current densities of various conductors by determining a field distribution from a current density theory (Biot-Savart) or from an inverted Biot-Savart calculation to determine the current densities directly [18,19].…”