Effect of interfacial iron oxidation on the exchange bias in CoO/Fe bilayers

Self-organized nano-structuring of CoO islands on Fe(001)

“…Furthermore, CoO films coupled to ferromagnetic substrates (like Fe), show the well-known and technologically important exchange bias effect [25,26], which makes this kind of systems even more appealing. Previous investigations on CoO/Fe(001) layered structures reported on complicated and extended chemical reactions at the interface, which is common when transition metal oxides are grown on the reactive Fe substrate [18,[27][28][29]. Scanning Tunneling Microscopy (STM) measurements observed a three-dimensional growth of CoO without any particular order [30].…”

Magnetic anisotropy at the buried CoO/Fe interface

“…This is true also for magnetic systems, where interface phenomena, such as exchange bias, have always been playing a major role, 6 and now are keys to obtaining an atomic-scale engineering of relevant magnetic features. 7,8 In the case of O/FM, several recent observations demonstrated how the interface chemical interactions directly influence the magnetic properties by, for instance, introducing uncompensated magnetic moments, 9 enhancing the coupling effects, 10 or even by creating such effects in unexpected ways, like the case of the nominally not exchange biased MgO/Fe interface. 11 Among O/FM systems, those containing antiferromagnetic (AF) oxides have been the subject of a great number of both experimental and theoretical investigations.…”

“…20 Very recently, we have demonstrated that it is possible to prepare a CoO/Fe(001) interface characterized by the absence of any Fe oxide, 21,22 which is a quite unique feature with respect to the common experimental situations. 10,19,23 This result has been accomplished by exploiting an ultra-thin Co buffer layer with a bct cubic structure. 21,24 In that case, the CoO films were also a) Currently at Institute of Applied Physics, TU Wien, Vienna, Austria b) Electronic mail: alberto.brambilla@polimi.it characterized by a well-ordered mesa mound morphology for CoO thicknesses above a few monolayers (ML), occurring on account of stress relaxation through the formation of a network of misfit dislocations.…”

Tailoring Perpendicular Exchange Bias Coupling in Au/Co/NiO Systems by Ion Bombardment

“…The Exchange-Bias (EB) effect in antiferromagnet (AFM)/ferromagnet (FM) thin film systems with in-plane [ 1 , 2 , 3 , 4 ] and perpendicular magnetic anisotropy (PMA) [ 5 , 6 ] is well known. In such systems, the direction of the exchange bias is initialized by field growth (layer deposition in an external magnetic field ( H dep ) [ 1 ]), by field cooling (FC) (heating and subsequent cooling of the layer system through the ordering temperature of the AFM layer in the presence of an applied magnetic field [ 7 ]), by thermally-induced ordering (annealing of AFM alloys to create the required AFM order [ 8 ]), or by light-ion bombardment-induced EB initialization (bombardment of the AFM/FM layer system by light ions in an external magnetic field ( H IB ) [ 9 ].…”