Tuning magnetostatic interaction and coercivity distributions of FeCo/Cu multilayer nanowire arrays by variation of magnetic and nonmagnetic layer aspect ratios

Abstract

FeCo/Cu multilayer NW arrays are fabricated using a pulsed electrodeposition method in 50 nm pore diameter anodic aluminum oxide templates. The magnetic layer (LFeCo) and nonmagnetic layer (LCu) thicknesses range between 23–225 and 2–50 nm, respectively. These layer designations make it possible to find a thin Cu layer, in which the magnetic behavior of multilayer NWs is similar to that of alloy NWs. A threshold LCu is also obtained, representing dual behavior of the coercive field in FeCo/Cu multilayer NWs. These behaviors, in turn, are associated with an increase in magnetizing and demagnetizing interactions, as evidenced by hysteresis curve and first-order reversal curve experiments. By extracting magnetic parameters such as the average coercive field, irreversible coercive field, magnetostatic interaction distribution, and reversibility, the magnetic behavior of FeCo/Cu multilayer NWs is comprehensively explored as a function of LFeCo.