Almost all electronic devices currently in use involve thin films of one material in contact with another material. The proper operation of a device depends strongly on the properties of the interfaces between the thin films.
By using electron spectroscopic techniques that can see several layers of atoms into a solid, we have been able to identify electronic states that exist only at the interface between the ferrimagnetic oxide Fe3O4 (the mineral magnetite) and antiferromagnetic CoO. Both of these oxides have potential applications in spintronics.
Interface electronic states were separated from those of bulk Fe3O4 and CoO by growing very thin films of CoO, one atomic layer at a time, onto Fe3O4 crystals. The interface states appear as soon as the first layer of CoO is deposited, but their amplitude soon decays as more and more CoO is grown on top of the film, in agreement with calculations.
|Amplitude of interface states vs. CoO thickness|