Probing Magnetism in Thin Films and Superlattices Using Polarized Neutron Reflectivity

In the last two decades, ultrathin films with artificially grown superlattices have been leading the field of new states of matter. The special properties and related functionalities of thin film heterostructures due to inherent conditions, such as electronic and orbital state reconstruction, symmetry breaking, interface alloying, and exotic magnetic ground states, have made these systems particularly interesting and challenging for understanding the fundamental mechanism and interaction at the interfaces. Interfaces of ultrathin heterostructures have been intensely researched for novel magnetic interaction in the field of fundamental research as well as for technological applications. However, one requires tools with good depth resolution and sensitivity toward magnetism in layered structures, especially interfaces. Polarized neutron reflectivity (PNR) is a unique non-destructive technique that has played a decisive role in the investigation of magnetic structures and in understanding the underlying physics in this rapidly developing field. Here we briefly discuss the application of this technique for studying structure and magnetism in several interesting ultrathin film systems.