M. Major

Recent Developments in Synchrotron Mössbauer Reflectometry

Synchrotron Mössbauer Reflectometry (SMR), the grazing incidence nuclear resonant scattering of synchrotron radiation, can be applied to perform depth-selective phase analysis and to determine the isotopic and magnetic structure of thin films and multilayers. Principles and methodological aspects of SMR are briefly reviewed. Off-specular SMR provides information from the lateral structure of multilayers. In anti-ferromagneticly coupled systems the size of magnetic domains can be measured.

Off-specular synchrotron Mossbauer reflectometry: A novel tool for studying the domain structure in antiferromagnetic multilayers

The off-specular (diffuse) nuclear resonant reflectivity of synchrotron radiation is a sensitive measure of the lateral autocorrelation of the magnetisation in thin films and multilayers. The width of the diffuse scattering peak measured at an electronically forbidden reflection is inversely proportional to the in-plane correlation length of the magnetisation direction. The average size of the in-plane antiferromagnetic domains is determined in different states of the same Fe/Cr superlattice. The hyperfine magnetic fields in coexisting small and large domains are measured independently.

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 μm measured in remanence on the Fe/Cr superlattice following magnetic saturation is in good agreement with semi-empirical model calculations.

Simulation of Antiferromagnetic Domain Formation History in Magnetic Multilayers

A Monte Carlo simulation of two-dimensional patch-domain formation and domain coarsening in antiferromagnetically coupled compensated multilayers with fourfold in-plane anisotropy is presented. The simulation accounts for both the emergence of small patch domains on unsaturation and domain coarsening on spin dispartial in hard direction. The simulated domain patterns are in good agreement with published Kerr microscopic images.

Simulation of domain formation and domain coarsening in antiferromagnetic multilayers

A Monte Carlo simulation of patch-domain formation and domain coarsening in antiferromagnetically coupled compensated multilayers with fourfold in-plane anisotropy is presented. The simulation accounts for both the emergence of small patch domains on unsaturation and the domain coarsening on spin flop. The autocorrelation function of the simulated domain pattern is in good agreement with published Kerr microscopic images.