Measurements of configurational anisotropy in isolated sub-micron square permalloy dots

摘要

We measure a shape dependent anisotropy energy in isolated square permalloy dots with characteristic dimensions as small as 200 nm. The magnetization behavior is characterized using the anisotropic magnetoresistance to determine the magnetic state of the sample. The behavior is consistent with the sample adopting a quasi-single-domain magnetization with a direction determined by an anisotropy intrinsic to the square geometry. We quantify the magnitude of this anisotropy through two independent measurements and confirm the observed magnetic behavior with micromagnetic simulations.