Larmor precession reflectometry for magnetic film studies

Polarized neutrons present Larmor pseudo-precession (LPP) when reflected from magnetic films. LPP is a result of quantum interference between the different spin components of the neutron wave reflected from the substrate and the front face of a magnetic film. This interference manifests as an effective rotation of the neutron polarization vector around the magnetization direction of the film. A new method is presented here, based on the effect of LPP, which allows the absolute direction of the magnetization vector inside a layer to be determined. This is not possible using conventional reflectometry techniques.