A low-noise ferrite magnetic shield

T. W. Kornack; S. J. Smullin; S. K. Lee; M. V. Romalis

doi:10.1063/1.2737357

A low-noise ferrite magnetic shield

T. W. Kornack, S. J. Smullin, S. K. Lee, M. V. Romalis

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

207 Scopus citations

Abstract

Ferrite materials provide magnetic shielding performance similar to commonly used high permeability metals but have lower intrinsic magnetic noise generated by thermal Johnson currents due to their high electrical resistivity. Measurements inside a ferrite shield with a spin-exchange relaxation-free atomic magnetometer reveal a noise level of 0.75 fT Hz-12, 25 times lower than what would be expected in a comparable μ -metal shield. The authors identify a 1f component of the magnetic noise due to magnetization fluctuations and derive general relationships for the Johnson current noise and magnetization noise in cylindrical ferromagnetic shields in terms of their conductivity and complex magnetic permeability.

Original language	English (US)
Article number	223501
Journal	Applied Physics Letters
Volume	90
Issue number	22
DOIs	https://doi.org/10.1063/1.2737357
State	Published - 2007

All Science Journal Classification (ASJC) codes

Physics and Astronomy (miscellaneous)

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10.1063/1.2737357

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title = "A low-noise ferrite magnetic shield",

abstract = "Ferrite materials provide magnetic shielding performance similar to commonly used high permeability metals but have lower intrinsic magnetic noise generated by thermal Johnson currents due to their high electrical resistivity. Measurements inside a ferrite shield with a spin-exchange relaxation-free atomic magnetometer reveal a noise level of 0.75 fT Hz-12, 25 times lower than what would be expected in a comparable μ -metal shield. The authors identify a 1f component of the magnetic noise due to magnetization fluctuations and derive general relationships for the Johnson current noise and magnetization noise in cylindrical ferromagnetic shields in terms of their conductivity and complex magnetic permeability.",

author = "Kornack, {T. W.} and Smullin, {S. J.} and Lee, {S. K.} and Romalis, {M. V.}",

note = "Funding Information: The authors acknowledge R. K. Ghosh for the initial design of parts of the apparatus. This research was supported by DARPA.",

year = "2007",

doi = "10.1063/1.2737357",

language = "English (US)",

volume = "90",

journal = "Applied Physics Letters",

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publisher = "American Institute of Physics",

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T1 - A low-noise ferrite magnetic shield

AU - Kornack, T. W.

AU - Smullin, S. J.

AU - Lee, S. K.

AU - Romalis, M. V.

N1 - Funding Information: The authors acknowledge R. K. Ghosh for the initial design of parts of the apparatus. This research was supported by DARPA.

PY - 2007

Y1 - 2007

N2 - Ferrite materials provide magnetic shielding performance similar to commonly used high permeability metals but have lower intrinsic magnetic noise generated by thermal Johnson currents due to their high electrical resistivity. Measurements inside a ferrite shield with a spin-exchange relaxation-free atomic magnetometer reveal a noise level of 0.75 fT Hz-12, 25 times lower than what would be expected in a comparable μ -metal shield. The authors identify a 1f component of the magnetic noise due to magnetization fluctuations and derive general relationships for the Johnson current noise and magnetization noise in cylindrical ferromagnetic shields in terms of their conductivity and complex magnetic permeability.

AB - Ferrite materials provide magnetic shielding performance similar to commonly used high permeability metals but have lower intrinsic magnetic noise generated by thermal Johnson currents due to their high electrical resistivity. Measurements inside a ferrite shield with a spin-exchange relaxation-free atomic magnetometer reveal a noise level of 0.75 fT Hz-12, 25 times lower than what would be expected in a comparable μ -metal shield. The authors identify a 1f component of the magnetic noise due to magnetization fluctuations and derive general relationships for the Johnson current noise and magnetization noise in cylindrical ferromagnetic shields in terms of their conductivity and complex magnetic permeability.

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VL - 90

JO - Applied Physics Letters

JF - Applied Physics Letters

IS - 22

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ER -

A low-noise ferrite magnetic shield

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