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Home Research Microfluidics/Biomedical

Planar Self-Biased Magnetic Resonance Microscopy "Lenses"

Research Area: Nanofabrication Year: 2008
Type of Publication: Article Keywords: magnetic resonance imaging, magnetic resonance microscopy, permanent magnet design, single-sided NMR, magnetic fields
Authors: Mladen Barbic; C. P. Barrett; L. Vltava; Teresa Emery; Chris Walker; Axel Scherer
Journal: Concepts in Magnetic Resonance Part B: Magnetic Resonance Engineering Volume: 33B
Number: 1 Pages: 21-31
Month: February
We present novel planar permanent magnet designs that create points above the plane where the magnitude of the static magnetic field is a local nonzero magnetic field point minimum. The designs represent potential magnetic resonance microscopy lenses where only a point region of the sample located in the focus spot of the structures is resonant. The high magnetic field curvatures of the lenses ensure that the regions outside of the focus spot are inactive or filtered out in the resonance detection process. In contrast to the original magnetic resonance lens design that required an applied uniform external bias field, the new designs are self-biased. Each planar permanent magnet design is accompanied by the equivalent planar single noncrossing conductor design. We also introduce the concept of Amperean current doubling in planar perpendicularly magnetized thin films that can be used to improve the performance of each permanent magnet design we present. We experimentally constructed macroscale representative permanent magnet and wire structures and measured their magnetic field properties that confirm our numerical predictions. Single conductor current-carrying designs are suitable for single layer lithographic fabrication, as we also experimentally demonstrate. Finally, we present the case that nanometer scale recording of perpendicular anisotropy thin magnetic films using presently available data storage technology can potentially provide the ultimate miniaturization of the presented designs.
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