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Magnetization Reversal in Magnetostatically Coupled Dot Arrays.

DE200241772

Publication Date	2002
Page Count	16
Abstract	The submicron permalloy dots with variable diameter and interdot distance were microfabricated into a rectangular lattice by means of e-beam lithography and lift-off techniques. The hysteresis loops exhibit characteristic magnetization reversal accompanied by nucleation and annihilation of magnetic vortices inside the dots. The magnetic response of the samples with well-separated elements is isotropic in the plane. The arrays with a small interdot distance show magnetic anisotropy with the easy axis along the shortest period in the array. This anisotropy is originated from the interdot magnetostatic interaction. The magnetostatic interaction is found to play an important role in determining the magnetization process for the dot arrays. For example, in the closely-packed (when interdot distance is smaller than dot radius) arrays so that d/R<1, the magnetostatic interaction decreases the vortex nucleation and annihilation fields, and increases the initial susceptibility.
Keywords	Magnetization Arrays Magnetic materials Ferromagnetism Magnetism Nucleation Annihilation Interactions
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Argonne National Lab., IL. Materials Science Div.; Tohoku Univ., Sendai (Japan).; Department of Energy, Washington, DC.
Supplemental Notes	Prepared in cooperation with Tohoku Univ., Sendai (Japan). Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200218

Magnetization Reversal in Magnetostatically Coupled Dot Arrays.

Magnetization Reversal in Magnetostatically Coupled Dot Arrays.
DE200241772

Publication Date	2002
Page Count	16
Abstract	The submicron permalloy dots with variable diameter and interdot distance were microfabricated into a rectangular lattice by means of e-beam lithography and lift-off techniques. The hysteresis loops exhibit characteristic magnetization reversal accompanied by nucleation and annihilation of magnetic vortices inside the dots. The magnetic response of the samples with well-separated elements is isotropic in the plane. The arrays with a small interdot distance show magnetic anisotropy with the easy axis along the shortest period in the array. This anisotropy is originated from the interdot magnetostatic interaction. The magnetostatic interaction is found to play an important role in determining the magnetization process for the dot arrays. For example, in the closely-packed (when interdot distance is smaller than dot radius) arrays so that d/R<1, the magnetostatic interaction decreases the vortex nucleation and annihilation fields, and increases the initial susceptibility.
Keywords	Magnetization Arrays Magnetic materials Ferromagnetism Magnetism Nucleation Annihilation Interactions
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Argonne National Lab., IL. Materials Science Div.; Tohoku Univ., Sendai (Japan).; Department of Energy, Washington, DC.
Supplemental Notes	Prepared in cooperation with Tohoku Univ., Sendai (Japan). Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200218