Experimental demonstration of shrinkage of magnetic domains in a superconductor/ferromagnetbilayer

Abstract

The shrinkage of magnetic domains in a superconductor/ferromagnet bilayeris studied experimentally using Pb as a superconductor and a garnet film withmaze domains as a ferromagnet. The effects of trapped flux in a superconductorand the pinning of magnetic domain boundaries are carefully minimized byusing a high-quality Pb single crystal and an AC demagnetization technique.A temperature independent shrinkage of magnetic domains by a factor ∼ 0.89 is obtained below the superconducting transition of Pb. The slightly suppressed shrinkageratio as compared with the theoretical prediction can be explained by a finite gap betweenthe Pb crystal and the garnet film.