Magnetization processes in micron-scale (CoFe/Pt)(n) multilayers with perpendicular anisotropy: First-order reversal curves measured by extraordinary Hall effect

Abstract

First-order reversal curves (FORCs) were recorded using the extraordinary Hall effect in micron-sized crosses of [Co90Fe10 (0.5?nm)/Pt (1.0?nm)] n multilayers with n?=?10, 20, and 50, which exhibit perpendicular magnetic anisotropy. Both the major hysteresis loop and the FORCs are compared to previous results, where the magnetization was measured directly on unpatterned stacks using alternating gradient force magnetometry. The FORC diagrams are dominated by two ?hysteron? peaks, and their separation increases when n becomes larger. A frustrated domain growth process is suggested in our n?=?20 and 50 sample