Magnetic properties of the Co/Alq(3) interface

Abstract

A method is described for measuring the magnetic integrity of ferromagnetic/organic interfaces that involves measuring the magnetic moment per unit area of bilayers with different ferromagnet thicknesses. The method is first used to determine the thickness of the oxide passivation layer on Co and Co90Fe10 (3.0 and 1.6 nm, respectively). The Alq3/Co interface is rather sharp, with roughness confined to about 3 monolayers of Co at the interface. The Co/Alq3 interface seems to be much rougher, with a dead layer that is several nanometers thick, However, this layer can be eliminated by capping the Alq3 layer with Al, so the dead layer is attributed to oxidation of the cobalt surface through the organic. The interface sharpness is improved when a 1 nm layer of LiF is inserted between Co and Alq3.