X-ray dichroism of Dy overlayers on a magnetic substrate

X-ray dichroism is a powerful tool to investigate magnetic properties of a large range of interesting materials. It appears however that also crystal fields play an important role in determining dichroism, especially at surfaces and interfaces. We examined the influence of a magnetic substrate on thin overlayers of Dy. We conclude that the role of the surface in the dichroism is greatly dominating over an eventual magnetic interaction with the substrate.