Stabilization of the ferromagnetic state in CoCrNi medium entropy alloy thin films.

This study considers the equiatomic CoCrNi alloy, a typical multi-principal element alloy (MPEA), which in bulk form, has shown superior mechanical properties and excellent oxidation and corrosion resistance. Such a combination of desirable characteristics motivates further research into the potential use of CoCrNi in thin-film form for various applications. This work aims to grow and optimize the deposition parameters of CoCrNi thin films and investigate their influence on the physical properties. The CoCrNi medium entropy alloy thin films were deposited onto Si/SiO2 substrates by direct current magnetron sputtering at different substrate temperatures and working gas pressures using a pre-alloyed target. The equiatomic polycrystalline composition was obtained at optimized pressure (2 mTorr) and temperature (400 °C). The electrical and magnetic properties were measured and contrasted with the physical properties of the bulk CoCrNi. The obtained magnetic properties indicate stabilization of the ferromagnetic phase in CoCrNi thin films. Anomalous Hall effect has been observed for all studied films. This work shows that deposition conditions (e.g., substrate temperature and working pressure) can be utilized to control the composition and microstructure and tailor the physical properties of the considered MPEA thin films for desired applications. [ABSTRACT FROM AUTHOR]