Micromagnetic reversal behavior of multiscale permalloy elements

Lorentz microscopy has been used to study the micromagnetic processes occurring during the reversal of multiscale permalloy elements. The elements, which have similar dimensions to write heads used in magnetic recording, typically have length scales varying from $10μm$ in the element “core” down to $100nm$ in the element “tip.” A discussion of the effect of varying the geometry and critical dimensions of the elements on the reversal behavior and switching fields is presented. While the magnetization processes in the core tend to be similar to what is observed in the absence of a tip, the presence of the core strongly influences the tip reversal, even for tips with widths of $100nm$⁠. The results demonstrate clearly the role played by shape anisotropy in complex shaped elements fabricated from an isotropic magnetic film.