Microscopic origin of finite inter-bilayer registry in DyOBr and DyOI

Distinguish random stacking faults, finite inter-bilayer correlation lengths, competing stacking domains, and more complex magnetic modulations as the microscopic origin of the imperfect inter-bilayer registry observed in DyOBr and DyOI.

Background

DyOBr and DyOI display sharp magnetic reflections together with broad, asymmetric Warren-like diffuse scattering. Reverse Monte Carlo refinements show that strong in-plane and intra-bilayer correlations coexist with only finite coherence between bilayers, but powder data do not uniquely determine the stacking arrangement.

The authors explicitly caution that the reverse Monte Carlo correlation profiles are not unique microscopic structures. Single-crystal diffuse neutron scattering is identified as the measurement needed to resolve whether the imperfect registry results from random stacking faults, finite correlation lengths, competing domains, or more complex modulations.