Layer-by-layer magnetometry of polarizing supermirrors

We investigate the remagnetization behaviour of remanent polarizing supermirrors by polarized neutron reflectometry. Such a mirror can be remagnetized in a magnetic field of 30mT. It is shown, that at lower fields, the mirror is not completely remagnetized, but the magnetization of the thinner layers can be flipped more easily than the magnetization of the thicker layers. With polarized neutron reflectometry, we are able to find out exactly how many layers are magnetized parallel and how many are magnetized antiparallel to the external field. Furthermore, information about structural and magnetic imperfections (roughness, domain formation) is available.