Transition metal elements in magnetron sputtered thin films

Abstract: Magnetron sputtering is a physical vapor deposition technique for thin film growth, and is the main research interest in our department. As a highly non-equilibrium process it may give rise to metastable phases brought from remote parts of the equilibrium phase diagrams or not present there altogether. We have been gradually increasing the use of transition metal elements in the films, which have the potential of bringing about effects of strong electron correlations. In this talk I will briefly review the various directions of our research into thin films containing transition metal elements, namely their incorporation into an amorphous matrix of light elements, VO2-based films exhibiting a metal-insulator transition, metallic glasses, and lastly the one I will mostly focus on: transition-metal dinitrides. Recent electronic structure calculations have predicted an extraordinary hardness of these materials due to the presence of the N-N single-bonded pernitride group in their structure. They were then synthesized in bulk in an equilibrium high-temperature high-pressure process. I will show how increasing the degree of ionization in the sputtering process can then enable the non-equilibrium effective high temperature and pressure to form dinitride films.