Artificial domain structures realized by local gallium focused Ion-beam modification of Pt∕Co∕Pt trilayer transport structure

Abstract

We demonstrate that a high-resolution Ga focused ion beam can be used to introduce artificial domain structures in Pt(1.6nm)∕Co(0.5nm)∕Pt(3.5nm) trilayer transport structures. We have used thin SiO2 overlayers to control the effective energy and dose of Ga ions at the Pt∕Co interface. The extraordinary Hall effect (EHE) was used to characterize the magnetic properties of the patterned films. Using 30keV Ga ions and SiO2 overlayer thicknesses in the range of 0–24nm, we achieve complete control of the coercive field of our Pt∕Co∕Pt trilayer structures. The magnetization reversal mechanism for an artificial domain of size of 3×0.5μm2 is investigated using EHE.