Formation and annihilation of edge walls in thin-film Permalloy strips

Comparison between magneto-resistance measurements and Kerr observations confirm that the formation and annihilation of edge walls in thin Permalloy strips, formed during rotation of an external field, is responsible for hysteresis in angular positioning sensors. The annihilation field required to avoid this unwanted behavior strongly depends on the strip cross section. Micromagnetic calculations assuming rectangular cross section yield higher absolute field values than those observed, but help to clarify the sensor behavior as field and material parameters are varied.