Talk:Coercivity

Old unsectioned comments

The graphical layout of this article looks terrible, but all the various positions I've tried for the figure and table still give a result that looks bad. Alison Chaiken 21:07, 18 February 2006 (UTC)[reply]

Table

Should the reference to the nanoparticles be a hyperlink in the table or is a listing at the end preferable? If in the table, some notation should be made to indicate nanoparticles rather than bulk or film. Alison Chaiken 00:10, 9 March 2006 (UTC)[reply]

table units

There are no units on the coercivity tables. I don't have access to a lot of the references, so I can't verify the units by myself. Can anybody help? -- 128.213.17.91, 17:53, 10 August 2006

Now the table has units, but they are non-SI units. According to the Wikipedia Manual of Style WP:UNITS, since this is a scientific article, and the table is not a direct quote, the coercivity values should be given in amperes per metre (A/m), not oersteds (Oe). D.keenan (talk) 22:21, 18 July 2012 (UTC)[reply]

I added the units. That made the text look really squeezed, so I collapsed the table and shortened the captions. RockMagnetist (talk) 23:53, 18 July 2012 (UTC)[reply]

The A/m values in the table are way off. 10,000 Oe (NdFeB) * 80 = 800,000 A/m. If we go with the proper 1000/4pi, it's still approximately 795,000 A/m. Most of them seem to be out by 10^6, but MA/m isn't any sort of standard I've ever run across. Also, most of the references for Oe values are to articles that require a subscription to find where the data is presented, are there more accessible articles available? DJBitterbarn (talk) 15:01, 19 July 2012 (UTC)[reply]

How embarrassing. I did the conversions the wrong way round. I fixed them. RockMagnetist (talk) 17:40, 19 July 2012 (UTC)[reply]

No, I just didn't have the time to fix them before and wanted to make very sure that I wasn't just misunderstanding some conversion or legend somewhere (that's been known to happen and I definitely could have been mistaken). But they work now. DJBitterbarn (talk) 08:58, 20 July 2012 (UTC)[reply]

Coercivity of Iron

The .05 value for iron is wrong -- I don't know where the author of the referenced article got it from. Silicon Irons, which have lower corcivity than plain iron, run between .4 and .9 oersted (and the article referenced actually says this). The actual value, as far as I can determine, is around 2 oersted. I've updated the article. Ahecht (talk) 15:27, 20 May 2008 (UTC)[reply]

other hysterisis graphics

Would it be useful to replace the second hysterisis loop graphic with a graphic of a soft magnetic materiel so people can see the difference between a high and low coercivity materiel? 32.145.11.31 (talk) 19:17, 9 December 2008 (UTC)[reply]

Collapse the table?

We have a difference of opinion on whether the table of coercivities should be collapsed. I believe that most readers will not care about these numbers, and the part they want to read is squeezed between the table and figures. If anyone does care, one click will give them the information. Anyone else want to weigh in? RockMagnetist (talk) 01:23, 4 January 2011 (UTC)[reply]

Given the article, people who read the article will doubtless find the table informative, particularly if it's not so badly laid out. I've therefore reformatted the table to be closer to the spirit (and hopefully letter) of WP:MOS and uncollapsed it.GliderMaven (talk) 01:37, 12 January 2014 (UTC)[reply]

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Please check intrinsic vs normal coercivity in the tables. They may be intrinsic.Jmv2009 (talk) 18:26, 25 February 2020 (UTC)[reply]

Confusing - normal vs intrinsic

I found the normal / intrinsic thing to be a bit confusing. I think it doesn't help that there are many "B vs H" curves that are actually plots of $\mu _{0}M$ vs H. This latter quantity is often given the label J (not to be confused with electric current density): https://www.magnet-sdm.com/2017/06/19/hysteresis-loop-demagnetization-curve-magnet/ . What's odd is that some people do magnetics without referring to magnetization at all. Example: [1], where they only use the term "intrinsic induction", referring to $B-\mu _{0}H$ (which is precisely $\mu _{0}M$ , or J). Then to make matters worse there is the whole confusion of gaussian electromagnetism vs SI electromagnetism.

So to be clear, my understanding is:

Normal coercivity: found as x-intercept on the proper B vs H curve, it is the negative H value required to drive B field to zero.
Intrinsic coercivity: found as x-intercept on M vs H curve (or J vs H curve), it is the negative H value required to drive magnetization M to zero.

If this is correct then the current article is wrong since it seemingly states the second definition for the first term. The article also needs a better graph, showing a high-coercivity material where the difference matters.

--Nanite (talk) 04:24, 3 January 2021 (UTC)[reply]

Values in Table Wrong

I work with magnets, and the coercivity values in the table are orders of magnitude off. For soft magnets typical values are ~1-100A/m, not a million or so times below that.

It seems roughly consistent with what you're saying -- iron (a soft magnetic material) is listed as 0.16 kA/m, and electrical steel as ~0.04 to 0.07 kA/m. I notice however that the references in the table are a bit poor. If you know of a better source please tell us about it. --Nanite (talk) 17:17, 16 November 2021 (UTC)[reply]