Spin-polarized neutron reflectometry investigation of rare-earth nitride thin films: DyN, HoN and ErN

Ferromagnetic semiconductors are expected to play a key role in future spintronics devices because they offer a rich set of functionality arising from the interplay of free electron-concentration and magnetism. However, candidate ferromagnetic semiconductors for wide-spread application are scarce. This has motivated the search for ferromagnetic semiconductors in a wide range of material families, for example the metal-nitrides and the dilute magnetic oxides. The existence of a true ferromagnetic semiconductor in these new families remains controversial Advanced experimental techniques are crucial to understand the interplay of chemistry, magnetism and finite-size effects that occur in nanoscale thin films containing these compounds. The spin-polarized option at the neutron reflectometer, Platypus, recently became operational at the OPAL research reactor, Lucas Heights. This powerful technique enables a determination of the depth dependency of the magnetization vector within a thin film structure with sub-nm resolution. In this work, we present recent experimental results from the study of the heavy rare-earth nitride thin films: ErN, HoN and DyN.