In this work, we present screening of magnetic monopole and dipole by the presence of a 20 nm aluminum cover layer on square artificial spin ice systems. Our measurements were performed by magnetic force microscopy on samples with and without aluminum at remanence, after application of successive external magnetic field steps. Experimental results show that both evolution of magnetization and monopole population under external field are affected by the aluminum presence. Very good agreement between those results and excitation model simulations was found when both emergent magnetic monopole and dipole strengths decrease on the presence of the aluminum cap. We suggest that the observed strength weakening of emergent particles occurs due to its field screening by aluminum-free electrons. The screening on the presented heterostructure could be used for devices design with different magnetic monopole mobility or for selective thermodynamic activation in samples close to superparamagnetic regime.
In this work we present emergent screening of magnetic monopole and dipole by the presence of 20nm aluminum cover layer onsquare artificial spin ice (ASI) systems. Our results were obtained in base of magnetic atomic force measurements, performedafter external magnetic field steps application. We show that the evolution of magnetization and monopole population is affectedby the aluminum presence and attribute that phenomena to the proximity effect, which is responsible for the magnetizationvanish of the first atomic layers at the ferromagnetic interface. Using experimental values to estimate the decrease in thenanomagnetic dipole value used in an emergent excitation model and in the switching field distribution heterogeneity usedin simulations, we observe a very good agreement among experimental and simulation results. The presented emergentscreening could be used in new ASI geometries for thermodynamic activation or proposition of devices with selective magneticmonopole mobility.
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