(A) study on patterned arrays of elliptical rings with non-uniform width and their ferromagnetic behavior

Abstract

Ferromagnetic rings with elliptical shape which have a different length between major and minor axis of ellipse have received much attention recently because of their stable magnetization reversal process in data storage. For magnetic patterns, Ni/Fe Permalloy ring arrays with non-uniform width were successfully fabricated by capillary force lithography and following etching process. The ring width of them and the ratio of length in each axis of ellipse could be precisely controlled by mold type, RIE time performed to polymer templates, molecular weight of polymer, and concentration of polymer solution. In addition, the ratio of length in each axis of ellipse affected the magnetization reversal process. Magnetic property of patterns was characterized by a magneto-optical Kerr effect (MOKE). Consequently, a ferromagnetic ring with non-uniform width which can not only induce a stable magnetization reversal process, but also possess a narrower switching field distribution was satisfactorily generated in this study.