Investigation of temperature dependent magnetic properties in irradiated Co/Pt multilayer devices using Extraordinary Hall effect measurements

Ultrathin Co/Pt multilayer system with strong perpendicular magnetic anisotropy (PMA) nowadays has been paid more attention to be used, as an ideal model system, in the study of current or field-driven domain wall motion [1, 2]. It has also shown ion irradiation technique is very effective to modify physical properties and anisotropy of magnetic nanostructures [3, 4]. The PMA in ultra-thin Co/Pt multilayers arising from interface and strain effects can be tuned by irradiation [5, 6]. Using focused ion beam (FIB) irradiation it is even possible to precisely dose and pattern arbitrary shapes and sizes in magnetic films. In this work, we report the experimental results using Ga ion FIB to irradiate Hall devices based on ultrathin Co/Pt multilayers. Temperature dependent magnetic properties in the irradiated devices were investigated by Extraordinary Hall effect (EHE) measurements. Pronounced differences in magnetic reversal of the irradiated devices were observed.