Experimental Evidence Of Magnetization Modification By Superconductivity In A Nb/Ni81fe19 Multilayer

We present experimental evidence of magnetization modification by superconductivity in a ferromagnet/superconductor heterostructure. By monitoring the magnetization as a function of time with a temperature change, we demonstrate that the magnetization of the ferromagnet is reduced when the heterostructure is cooled below the superconducting transition temperature T-c. The magnitude of the reduction increases with lower cooling temperature. Besides, the M(T) curve measured in zero field exhibits irreversibility between cooling and warming branches above T-c. These results can be qualitatively understood in terms of the mutual interactions between ferromagnetism and superconductivity.