Talk:Magnetic susceptibility

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1 Susceptibility versus Relative Permeability
2 Values of Volume Magnetic Susceptibility of Pure Water
3 Recent Edits introducing Intensity of magnetization
4 Recent edit of volume susceptibility definition
5 Notes

[edit] Susceptibility versus Relative Permeability

The discussion about the susceptibility is to know where it is inferior or superior to 1 and not positive or negative.

I think the article is correct as it stands in speaking about the distinction between χ positive versus negative. The permeability of the material depends not on χ alone, but rather on ( 1 + χ ). This factor is called the relative permeability of the material. So if χ is positive, the relative permeability is greater than 1; and if χ is negative, the relative permeability is less than 1. I am not 100 percent sure, but could that answer the concern that you have raised? -- Rdrosson 23:52, 21 October 2005 (UTC)

All right, but as you first wrote it, it wasn't that clear. Good job!

Mistake on this page. The magnetization is defined as magnetic moment per unit mass. It should be magnetic moment per unit volume. (Check the units). Also would be nice to link magnetic dipole moment (to Magnetic moment).

I don't believe the article should start of "In electrical engineering." Magnetic susceptibility is a physical parameter independent of any discipline. If it is tied to any discipline it should be physics but in general the article shouldn't tie susceptibility to any parameter.

[edit] Values of Volume Magnetic Susceptibility of Pure Water

According to the book "Spin Dynamics: Basics of Nuclear Magnetic Resonance" by M. H. Levitt, the volume magnetic susceptibility of pure water is $- 90 x 10 - 6$ in SI unit. In the current (11 April 2006) Wikipedia article, it appears that the susceptibility value is $- 5.72 x 10 - 6$ in SI and $- 7.19 x 10 - 7$ in cgs. Compared to the value in Levitt's, the cgs value makes sense, but the SI value do not. In fact, the number 5.72 might have come from $7.19 / 4π$ , which is wrong calculation -- division instead of multiplication, combined with a wrong order of magnitude. Overall, I think the SI value in the Wikipedia article should be corrected to the value in Levitt's book, $- 90 x 10 - 6$ .

[edit] Recent Edits introducing Intensity of magnetization

Please see the following forum ^[1] for discussion of the notion of Intensity of magnetization. Recent edits by BehzadAhmadi had a number of errors, for example: the units in the first equation, $\mathbf{I} = \chi_{v} \mathbf{H}$ , were not consistent, since $χ v$ is normally defined as a dimensionless quantity. Therefore, to avoid any more confusion in this historically confusing area, the edits were reverted to the last correct version. Xenonice (talk) 03:14, 23 January 2008 (UTC)

[edit] Recent edit of volume susceptibility definition

Somebody (130.88.52.80) "corrected" one of the volume susceptibility formulae to be

$\mu = 1/(1 - \chi_v) \,$ ,

as opposed to the standard definition^[2]

$\mu = \mu_0(1+\chi_v) \,$ .

Please refrain from such edits in the future (i.e. edits that replace an established formula with another that directly contradicts it), it would be better to discuss such changes here first. Xenonice (talk) 03:14, 23 January 2008 (UTC)

[edit] Notes

^ http://info.ee.surrey.ac.uk/Workshop/advice/coils/mu/
^ For example, see Eq. 6 in Kuchel, P. W.; Chapman, B. E.; Bubb, W. A.; Hansen, P. E.; Durrant, C. J.; and Hertzberg, M. P. (2003). "Magnetic susceptibility: Solutions, emulsions, and cells". Concepts in Magnetic Resonance A 18A (1): 56-71. doi:10.1002/cmr.a.10066.