SmN and DyN: Effect of the nitrogen to rare earth flux ratio on the structural, transport, and magnetic properties

We report on the effect of the nitrogen to rare earth (N2/RE) flux ratio on the structural, transport, and magnetic properties of samarium nitride (SmN) and dysprosium nitride (DyN) thin films. Both materials display a reduced lattice constant when the N2/RE flux ratio decreases, i.e., with increased nitrogen vacancies (VN) concentration. The films show several orders of magnitude increase in the electrical resistivity with increased N2/RE flux ratio. Finally, magnetic measurements on DyN films display a deviation from the free ion moment at low temperature, which is eased in more conductive films. This was interpreted as a further reduction in the quenching of the orbital angular momentum caused by the increased VN concentration. The Curie temperature was also found to increase with VN.