Anomalous Hall effect in a double-layer Ni / Gd2O3 nanosized films

Abstract

It has been shown by the anomalous Hall effect method that upon contact of layers of iron group metal (Ni) and REM oxide (Gd₂O₃) nanosized films, an increase by 15–35 % in the magnetization of the ferromagnetic metal is observed. Such an increase does not require energy consumption and the use of amplifying equipment, is very promising for nanotechnology. The enhancement of magnetization is due to the appearance in the contact region of the exchange f–d interaction between atoms with empty d– and f–electron shells that are parts of the layers. The exchange interaction stimulates the ordering of the magnetic structure of the ferromagnetic metal and an increase in its magnetization. The possibility of exchange f–d interaction in the region of contact of layers of metals of the iron group and REM oxides was confirmed by the method of electronic paramagnetic resonance in our previous studies. This paper also shows the lack of influence on the growth of magnetization of other possible mechanisms due to the difference in the parameters of the crystal lattice, resistance, magnetic and termomagnetic properties of the contacting layers.

A mathematical connection is found of the potential of Hall contacts and additional magnetization stimulated by the exchange f–d interaction. Using this relationship, the mechanism of the effect of an external magnetic field on additional magnetization had revealed. It is shown that this magnetization depends on the ratio of the thicknesses of the Ni and Gd₂O₃ layers. It has been found that the vector of this magnetization is directed from the Gd₂O₃ layer to the Ni layer.