Epitaxial thin film studies: a time-of-flight neutron diffraction perspective

Neutron diffraction is the primary technique to study magnetic long-range ordering in crystalline materials. Historically this method required a large sample volume, making it unsuitable for application to thin film samples. In this perspective paper, we would like to bring the thin film community's attention to new opportunities and capabilities offered by the current state of the art instrumentation. In particular, we focus on recent developments on the time-of-flight cold neutron diffractometer WISH located at the ISIS neutron and muon source. Starting from the description of a typical thin film neutron diffraction experiment, we highlight the advantages provided by the Laue time-of-flight technique with some key examples taken from recent literature. These examples represent case studies of functional materials where neutron diffraction has provided crucial information about their magnetic structures and domain patterns. Finally we discuss some future opportunities and upgrades which will further push the limit of the neutron diffraction technique in the field of epitaxial magnetic thin films and heterostructures.