Polarized neutron reflectometry study on 60×Fe₃₁Co₆₈V₁/Ti₇₅Zr₂₅ multilayers

We present a study of the magnetic behavior of 60×Fe₃₁Co₆₈V₁/Ti₇₅Zr₂₅ multilayers with applied field along the easy and hard axis. We performed polarized neutron reflectometry experiments with polarization analysis at a time-of-flight setup. At applied fields above 16 kA/m the sample was magnetically saturated. The reduction of high-order Bragg superlattice reflections is interpreted as inter-layer roughness of about 2 nm. In the low-field region, the first-order Bragg reflection consists of a broad and a sharp peak, indicating separate contributions from macroscopic magnetically ordered and disordered regions. Spin flipped neutron reflectivities observed at low fields are attributed to domains with local easy axis not parallel to the applied field. The increase in spin flipped neutron reflectivity at high incident angle is ascribed to domains sizes in the order of tens of microns.