Topical Review of Quantum Materials and Heterostructures Studied by Polarized Neutron Reflectometry

A review of the applications of polarized neutron reflectometry (PNR) for the investigation of quantum materials is provided. Recent studies of superconductors, strongly correlated oxides, hydrogen‐induced modifications, topological insulators and chiral magnets are highlighted. The PNR technique uses a quantum beam of spin‐polarized neutrons to measure the nanomagnetic structure of thin films and heterostructures, with a sensitivity to magnetization at the scale of 10–2000 emu cm −3 and a vertical spatial resolution of 1–500 nm. From simple beginnings studying the magnetic flux penetration at superconducting surfaces, today the PNR technique is widely used for investigating many different types of thin film structures, surfaces, interfaces, and 2D materials. PNR measurements can reveal a number of details about magnetic, electronic, and superconducting properties, in tandem with chemical information including the stoichiometry of light elements such as oxygen and hydrogen.