Peer-Reviewed Journal Details
Mandatory Fields
Maity, Tuhin; Roy, Saibal
2017
March
IEEE Magnetics Letters
Manipulation of magnetic properties by tunable magnetic dipoles in a ferromagnetic thin film
Validated
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Optional Fields
Nanomagnetics Magnetic anisotropy Magnetic film Nanoimprint lithography Soft magnetic materials Magnetostatics Perpendicular magnetic anisotropy Magnetic domains Magnetic resonance imaging Magnetic films Magnetostatic waves
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We demonstrate how a unique nanomodulation within a continuous ferromagnetic film can induce magnetic dipoles at predefined, submicrometer scale locations, which can tune the global magnetic properties of the film due to dipole-dipole interactions. Arrays of tunable magnetic dipoles are generated with in-plane and out-of-plane directions, which can be rotated in-plane within the three-dimensional (3-D) modulated structure of a continuous film. In-plane magnetic dipole rotation enables a methodology to control overall magnetic properties of a ferromagnetic thin film. Formation of magnetic dipoles and their tunability were studied in detail by magnetic force microscopy, high-resolution magnetic measurements, and micromagnetic simulation of a nanomodulated Ni45Fe55 alloy film. A pattern larger than a single magnetic domain would normally form a vortex in the remanent state. However, here the unique 3-D nanostructure prevents vortex formation due to the competition between in-plane and out-of-plane dipole-dipole interaction giving rise to a metastable state. Experimentally, at zero remanence, the magnetization goes through a transformation from a metastable to a stable state, where the dipole-dipole interaction depends on their geometrical arrangement. Thus, the magnetic properties of the continuous film can be varied by the proposed pattern geometry. A detail analytical study of the dipolar energy for the system agrees well with the experimental and simulated results.
1949-307X
10.1109/LMAG.2017.2685585
Grant Details