Specular and off-specular Synchrotron Mossbauer Reflectometry:: Applications to thin film magnetism

Synchrotron Mossbauer Reflectometry (SMR) is a novel tool for studying the magnetic structure of multilayers. The orientation of the layer magnetisation in an antiferromagnetically coupled multilayer is determined from the intensity of the pure nuclear reflection in specular time-integral SMR experiments. The value of the saturation field is estimated with high accuracy. The bulk spin-flop transition in an Fe/Cr superlattice of fourfold in-plane magnetocrystalline anisotropy is demonstrated. The width of the off-specular (diffuse) scattering peak is a measure of the in-plane antiferromagnetic domain size. The domain correlation length of 2.6 mum measured in remanence on the Fe/Cr superlattice following magnetic saturation is in good agreement with semi-empirical model calculations.