The influence of mechanical stresses on the magnetic properties of NiFe$_{2}$O$_{4}$ and CoFe$_{2}$O$_{4}$ films

We have studied the influence of mechanical stresses on the magnetic properties of nickel ferrite (NiFev) and cobalt ferrite (CoFe$_{2}$O$_{4}$) films deposited on sapphire substrates with $a$- and $c$-oriented step terrace nanostructures. It is established that compressive stresses favor enhancement of the coercive field in thin ferrite films in the strain direction. Films of magnetically soft nickel ferrite with a room-temperature coercive field of 32.5 mT were obtained.