Microscale magnetic compasses

Hidetsugu Shiozawa; Desai Zhang; Michael Eisterer; Paola Ayala; Thomas Pichler; Martha McCartney; David Smith

doi:10.1063/1.4985838

Microscale magnetic compasses

Hidetsugu Shiozawa, Desai Zhang, Michael Eisterer, Paola Ayala, Thomas Pichler, Martha McCartney, David Smith

Research output: Contribution to journal › Article › peer-review

Abstract

Microscale magnetic compasses have been synthesized with high yield. These ferromagnetic iron carbide nano-particles, which are encapsulated in a pair of parallel carbon needles, change their orientation in response to an external magnetic field. Electron holography reveals magnetic fields confined to the vicinity of the bicone-shaped particles, which are composed of only a few ferromagnetic domains. Aligned magnetically and encapsulated in an acrylate polymer matrix, these micro-compasses exhibit anisotropic bulk magnetic permeability with an easy axis normal to the needle direction that can be understood as a result of the anisotropic demagnetizing field of a non-spherical single-domain particle. This novel type of material with orthogonal magnetic and structural axes could be highly useful as magnetic components in electromagnetic wave absorbent materials and magnetorheological fluids.

Original language	English (US)
Article number	094301
Journal	Journal of Applied Physics
Volume	122
Issue number	9
DOIs	https://doi.org/10.1063/1.4985838
State	Published - Sep 7 2017

ASJC Scopus subject areas

General Physics and Astronomy

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10.1063/1.4985838

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abstract = "Microscale magnetic compasses have been synthesized with high yield. These ferromagnetic iron carbide nano-particles, which are encapsulated in a pair of parallel carbon needles, change their orientation in response to an external magnetic field. Electron holography reveals magnetic fields confined to the vicinity of the bicone-shaped particles, which are composed of only a few ferromagnetic domains. Aligned magnetically and encapsulated in an acrylate polymer matrix, these micro-compasses exhibit anisotropic bulk magnetic permeability with an easy axis normal to the needle direction that can be understood as a result of the anisotropic demagnetizing field of a non-spherical single-domain particle. This novel type of material with orthogonal magnetic and structural axes could be highly useful as magnetic components in electromagnetic wave absorbent materials and magnetorheological fluids.",

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AU - Shiozawa, Hidetsugu

AU - Zhang, Desai

AU - Eisterer, Michael

AU - Ayala, Paola

AU - Pichler, Thomas

AU - McCartney, Martha

AU - Smith, David

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AB - Microscale magnetic compasses have been synthesized with high yield. These ferromagnetic iron carbide nano-particles, which are encapsulated in a pair of parallel carbon needles, change their orientation in response to an external magnetic field. Electron holography reveals magnetic fields confined to the vicinity of the bicone-shaped particles, which are composed of only a few ferromagnetic domains. Aligned magnetically and encapsulated in an acrylate polymer matrix, these micro-compasses exhibit anisotropic bulk magnetic permeability with an easy axis normal to the needle direction that can be understood as a result of the anisotropic demagnetizing field of a non-spherical single-domain particle. This novel type of material with orthogonal magnetic and structural axes could be highly useful as magnetic components in electromagnetic wave absorbent materials and magnetorheological fluids.

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Microscale magnetic compasses

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