Local Observation of Field Polarity Dependent Flux Pinning by Magnetic Dipoles.
A scanning Hall probe microscope is used to study flux pinning in a thin superconducting Pb film covering a square array of single-domain Co dots with in-plane magnetization. We show that single flux quanta of opposite sign thread the superconducting film below T(c) at the opposite poles of these dipoles. Depending on the polarity of the applied field, flux lines are attracted to a specific pole of the dipoles, due to the direct interaction with the vortexlike structures induced by the local stray field.
Van Bael MJ
Laboratorium voor Vaste-Stoffysica en Magnetisme, K. U. Leuven, Celestijnenlaan 200D, B-3001 Leuven, Belgium.
Bekaert
J
Temst
K
Van Look L
Moshchalkov
VV
Bruynseraede
Y
Howells
GD
Grigorenko
AN
Bending
SJ
Borghs
G