A. K. Suszka, F. S. Bergeret, A. Berger
We have studied the interaction between magnetism and superconductivity in a
pseudo-spin-valve structure consisting of a Co/Cu/Py/Nb layer sequence. We are
able to control the magnetization reversal process and monitor it by means of
the giant magnetoresistance effect during transport measurements. By placing
the superconducting Nb-film on the top of the permalloy (Py) electrode instead
of putting it in between the two ferromagnets, we minimize the influence of
spin scattering or spin accumulation onto the transport properties of Nb.
Magnetotransport data reveal clear evidence that the stray fields of domain
walls (DWs) in the pseudo-spin-valve influence the emerging superconductivity
close to the transition temperature by the occurrence of peak-like features in
the magneto-resistance characteristic. Direct comparison with magnetometry data
shows that the resistance peaks occur exactly at the magnetization reversal
fields of the Co and Py layers, where DWs are generated. For temperatures near
the superconducting transition the amplitude of the DW-induced
magnetoresistance increases with decreasing temperature, reaching values far
beyond the size of the giant magnetoresistive response of our structure in the
normal state.
View original:
http://arxiv.org/abs/1202.0715
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