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Calculation of magnetic field noise from high-permeability magnetic shields and conducting objects with simple geometry

J. Appl. Phys. 103, 084904 (2008); doi:10.1063/1.2885711

Published 23 April 2008

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S.-K. Lee and M. V. Romalis
Physics Department, Princeton University, Princeton, New Jersey 08544, USA
High-permeability magnetic shields generate magnetic field noise that can limit the sensitivity of modern precision measurements. We show that calculations based on the fluctuation-dissipation theorem allow quantitative evaluation of magnetic field noise, either from current or magnetization fluctuations, inside enclosures made of high-permeability materials. Explicit analytical formulas for the noise are derived for a few axially symmetric geometries, which are compared with results of numerical finite element analysis. Comparison is made between noises caused by current and magnetization fluctuations inside a high-permeability shield and also between current-fluctuation-induced noises inside magnetic and nonmagnetic conducting shells. A simple model is suggested to predict power-law decay of noise spectra beyond a quasi-static regime. Our results can be used to assess noise from existing shields and to guide design of new shields for precision measurements. ©2008 American Institute of Physics
History: Received 5 October 2007; accepted 22 December 2007; published 23 April 2008
Permalink: http://link.aip.org/link/?JAPIAU/103/084904/1
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KEYWORDS and PACS

Keywords
PACS
  • 75.60.Ej
    Magnetization curves, hysteresis, Barkhausen and related effects
  • 72.70.+m
    Noise processes and phenomena in electronic transport
  • YEAR: 2008

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PUBLICATION DATA

ISSN:
0021-8979 (print)   1089-7550 (online)
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REFERENCES (24)
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  1. A. J. Mager, IEEE Trans. Magn. 6, 67 (1970).
  2. J. C. Allred, R. N. Lyman, T. W. Kornack, and M. V. Romalis, Phys. Rev. Lett. 89, 130801 (2002).
  3. T. Varpula and T. Poutanen, J. Appl. Phys. 55, 4015 (1984).
  4. J. R. Clem, IEEE Trans. Magn. 23, 1093 (1987).
  5. C. Henkel, Eur. Phys. J. D 35, 59 (2005).
  6. J. Nenonen, J. Montonen, and T. Katila, Rev. Sci. Instrum. 67, 2397 (1996).
  7. C. T. Munger, Jr., Phys. Rev. A 72, 012506 (2005).
  8. D. Budker, D. Kimball, and D. DeMille, Atomic Physics (Oxford U. P., Oxford, 2004), Chap. 9.
  9. B. J. Roth, J. Appl. Phys. 83, 635 (1998).
  10. H. B. Callen and T. A. Welton, Phys. Rev. 83, 34 (1951).
  11. J. A. Sidles, J. L. Garbini, W. M. Dougherty, and S. -H. Chao, Proc. IEEE 91, 799 (2003).
  12. G. Durin, P. Falferi, M. Cerdonio, G. A. Prodi, and S. Vitale, J. Appl. Phys. 73, 5363 (1993).
  13. T. W. Kornack, S. J. Smullin, S. -K. Lee, and M. V. Romalis, Appl. Phys. Lett. 90, 223501 (2007).
  14. D. Lin, P. Zhou, W. N. Fu, Z. Badics, and Z. J. Cendes, IEEE Trans. Magn. 40, 1318 (2004).
  15. For low-conductivity soft ferromagnets, so-called excess or residual loss often dominates eddy current loss calculated with static bulk conductivity. In such cases we assume that the effect is included in an appropriately redefined sigma=sigma(f).
  16. P. Mazzetti and G. Montalenti, J. Appl. Phys. 34, 3223 (1963).
  17. This comes from the fact that for a given shield size and shape, the reluctance of the portion of the magnetic circuit that goes through the shield scales with the thickness and the permeability as Rmagn[proportional]1/(µrt). Therefore qualitative distribution of field lines around the shield should not change as µr and t vary while keeping their product constant. The other length scale relevant to the problem is a, which leads to the dimensionless parameter specified.
  18. Obviously this does not hold at the corners of a closed cylindrical shield. However, numerical finite-element calculations in Appendix A indicate that errors in noise due to these localized points are at most on the order of 1%.
  19. W. R. Smythe, Static and Dynamic Electricity (McGraw-Hill, New York, 1968), pp. 188–190.
  20. The integrand diverges at x[prime]=1/2, but the integral converges when the upper limit of integral approaches 1/2 from below.
  21. J. Nenonen and T. Katila, in Biomagnetism '87, edited by K. Atsumi, M. Kotani, S. Ueno, T. Katila, and S. J. Williamson (Denki U. P., Tokyo, 1988), p. 426.
  22. See their Eq. (45) and an expression in the following paragraph.
  23. See their Eq. (5) in the case d>>t.
  24. This is the case after correcting the definition of zeta2 by multiplying it with z2 in order to render it dimensionless as claimed.

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