Active participation of “inert” YSZ substrates on interface formation in Fe3O4/YSZ heterostructures

The bulk and emerging interface properties of magnetite Fe3O4/YSZ(001) heterostructures grown by pulsed laser deposition are investigated. Fe3O4 thin films (4–38 nm) grow epitaxially in (111) orientation and undergo a Verwey transition at max. TV = 117±0.6K. Surprisingly, the formation of interfacial Fe2O3 phase is observed albeit the quasi-inert properties of yttrium-stabilized zirconia (YSZ). Possible mechanisms include either (i) thermodynamically induced interfacial redox reaction at the YSZ substrate surfaces or (ii) oxygen diffusion from the outside atmosphere, as YSZ is a very good oxygen ion conductor. Hence, substrate-assisted oxygen supply may enable the control of emerging interface functionalities