Related papers: Dendritic flux patterns in MgB2 films
Magneto-optical imaging was used to study a zero-field-cooled MgB2 film at 9.6K where in a slowly increasing field the flux penetrates by abrupt formation of large dendritic structures. Simultaneously, a gradual flux penetration takes…
Anisotropic penetration of magnetic flux in MgB2 films grown on vicinal sapphire substrates is investigated using magneto-optical imaging. Regular penetration above 10 K proceeds more easily along the substrate surface steps, anisotropy of…
Magneto-opitcal studies of a c-oriented epitaxial MgB2 film show that below 10 K the global penetration of vortices is dominated by complex dendritic structures abruptly entering the film. We suggest that the observed behavior is due to a…
Magneto-optical imaging reveals that in superconducting films of MgB2 a transport current creates avalanche-like flux dynamics where highly branching dendritic penetration patterns are formed. The instability is triggered when the current…
The penetration of magnetic flux into a thin superconducting film of Nb3Sn with critical temperature 17.8K and critical current density 6MA/cm^2 was visualized using magneto-optical imaging. Below 8 K an avalanche-like flux penetration in…
Using magneto-optical imaging the phenomenon of dendritic flux penetration in superconducting films was studied. Flux dendrites were abruptly formed in a 300 nm thick film of MgB2 by applying a perpendicular magnetic field. Detailed…
Magnetic instability in both ultra-pure and carbon-doped MgB2 films is investigated by magneto-optical imaging, transport and bulk magnetization measurements. In the carbon-doped MgB2 thin film, familiar dendritic flux-jump patterns were…
We explore the flux-jump regime in type-II Pb thin films with a periodic array of antidots by means of magneto-optical measurements. A direct visualization of the magnetic flux distribution allows to identify a rich morphology of flux…
Magnetic relaxation and critical current density have been measured on a $MgB_2$ thin film in a wide region of temperature with the magnetic field up to 8 T. The irreversibility line has also been determined. It is found that the relaxation…
Magneto-optical imaging was used to observe flux dendrites with opposite polarities simultaneously penetrate superconducting, ring-shaped MgB$_2$ films. By applying a perpendicular magnetic field, branching dendritic structures nucleate at…
MgB2 tapes with high critical current have a significant technological potential, but can experience operational breakdown due to thermomagnetic instability. Using magneto-optical imaging the spatial structure of the thermomagnetic…
We present a detailed magneto-optical investigation of the magnetic flux penetration in polycrystalline MgB2 slabs made by direct reaction of B and Mg. Our results unambiguously indicate a uniform, Bean critical state magnetization behavior…
We report the growth of high-quality c-axis-oriented epitaxial MgB2 thin films by using a pulsed laser deposition technique. The thin films grown on (1`1 0 2) Al2O3 substrates show a Tc of 39 K. The critical current density in zero field is…
We report the growth and properties of epitaxial MgB2 thin films on (0001) Al2O3 substrates. The MgB2 thin films were prepared by depositing boron films via RF magnetron sputtering, followed by a post-deposition anneal at 850C in magnesium…
We report a detailed comparison of experimental data and theoretical predictions for the dendritic flux instability, believed to be a generic behavior of type-II superconducting films. It is shown that a thermo-magnetic model published very…
Flux distributions in thin superconducting NbN films placed in a perpendicular magnetic field have been studied using magneto-optical imaging. Below 5.5 K the flux penetrates in the form of abrupt avalanches resulting in dendritic…
An one-dimensional model of magnetic flux penetration into thin strip-like superconductive film is subject to numerical analysis which combines explicit account for specific oblate geometry of magnetic field lines around the film and a…
The effects of neutron irradiation on normal state and superconducting properties of epitaxial magnesium diboride thin films are studied up to fluences of 1020 cm-2. All the properties of the films change systematically upon irradiation.…
Angle dependent torque measurements have been carried out on the organic superconductor, kappa-(ET)2Cu(NCS)2 at extremely low temperatures (25 - 300 mK). Magneto-thermal instabilities are observed in the form of abrupt magnetization (flux)…
We develop a fast numerical procedure for analysis of nonlinear and nonlocal electrodynamics of type-II superconducting films in transverse magnetic fields taking into account realistic boundary conditions. Using this procedure we explore…