The setup

Polarized-ligh microscope is used with the flow-type liquid helium cryostat to conduct experiments at temperatures between 3.6 K and 350 K and in magnetic fields up to 0.5 Tesla.

Forming Bean critical state in Nb strip with pinning. Sample was cooled in 700 Oe to T=3.8 K whence magnetic field was gradually decreased.

Flash player should be installed to see the movies.
To play the movie, right-click on the images and select "PLAY".

Building magnetic flux zebra in a granular Pb film

[Flash player no longer available]

Yellow and green colors represent magnetic flux of opposite sign. External magnetic field increases and decreases, becomes negative and so on. In each cycle, the maximum amplitude decreases. At the end, sample has trapped ripples of positive and negative flux. T=3.8 K.
December 2005

Flux penetration into Meissner and remanent state of Nb strip