Abstract
Polarized neutron and X-ray reflectivity are complementary tools used to measure the depth profile of magnetic thin films. In this work, permalloy thin films were epitaxially deposited on Mo buffered Al 2 O 3 (1-100) substrates with a Co interlayer and without a Co interlayer. The interface structure between the permalloy and the Co layers, determined by X-ray reflectivity alone, was insensitive, due to the low contrast of the electron density between these two adjacent layers. It can however, be determined by polarized neutron reflectivity, due to the large difference of the nuclear scattering lengths and magnetic moments between these two layers.