Magnetic Characteristics of Fine Permalloy Patterns

The magnetization behavior of patterned Permalloy film used in bubble memory elements is described. A total of 4.6 × 10⁶ pattern elements were formed in Permalloy film evaporated onto a GGG substrate, spaced at a period of 4.5 ¿m. In-plane magnetization curves showed almost no change when a bias field was applied normal to the film, and patterning resulted in a strong shape effect. The in-plane magnetization curves had bends which were attributed to different magnetization characteristics prevailing in different portions of each pattern.