Title of article :
Observation of dynamic interaction of vortices with ion irradiated defects by Lorentz microscopy
Author/Authors :
Harada، نويسنده , , K. and Matsuda، نويسنده , , Emmanuel T. and Kasai، نويسنده , , H. and Kamimura، نويسنده , , O. and Tonomura، نويسنده , , A.، نويسنده ,
Abstract :
The dynamic interaction of vortices (quantized magnetic flux lines) with pinning centers was observed directly by Lorentz microscopy using a 300 kV field emission electron microscope. To clarify the pinning effect on the vortex configuration, we produced a defect array in a single-crystalline thin film of Nb by irradiating it with an ion beam. The vortices could not form a single-crystalline lattice structure but became divided into domain structures due to the existence of the defect array. When the magnetic field was changed, all the domains resisted being moved for a while, and then some domain boundaries suddenly began to move in an avalanche manner and to break down into pieces that flowed like a “river”, that flowed along the domain boundaries located near the defect. At higher temperatures, the “river” became wider and finally the vortex lattice flowed while keeping its lattice form.
Keywords :
Vortex , superconductor , Lorentz microscopy , Electron holography
Journal title :
Astroparticle Physics