The Hysteresis Loop of Raw Iron: Understanding Coercivity and Magnetization

[Dash-IQ]

The "area" of the hysteresis loop depends on the coercivity, the coercivity of raw iron(Wrought iron) is 2 Oe(160 A/m).

If 1 gauss = 10³/ 4∏ = 79.58 A/m(I'm not sure about this, http://www.sste.mmu.ac.uk/users/shoon/pers_page/envmagn_tables_anal/Mag-Units-Tables-New.pdf(under "General working conversions" page 2)).

A field of 2 gauss can magnetize/demagnetize this material?!
The work done is amazingly diminutive!
Is this right?!

I imagine the hysteresis loop being extremely narrow, which makes sense since most "soft" iron materials are like that. They are easy to magnetize and demagnetize.

 

[UltrafastPED]

Your information probably came from this book:
http://books.google.com/books?id=G0cOAAAAYAAJ&pg=PA133#v=onepage&q&f=false
"Dynamo-electric machinery: a manual for students of electrotechnics" (1896)

The discussion starting on page 133 may help you work out the answer.Note that the units of gauss (=10^-4 tesla) is not the same as the oersted; see
http://en.wikipedia.org/wiki/Oersted

 

[Dash-IQ]

Note that the units of gauss (=10^-4 tesla) is not the same as the oersted; see
http://en.wikipedia.org/wiki/Oersted

I assumed 2 gauss = 160 A/m based on the conversion table present in the source, I must review this.
What about the coercively of raw iron? When it's equal to 160 A/m is that considered to be a small value?
It has the tendency to become magnetized and de-magnetized easily?

I don't have any perspective of this, because I'm new at this subject. However, when comparing it to Neodymium-iron-boron I realize the major difference.
neodymium-iron-boron = 9x10⁵ A/m.

 

[UltrafastPED]

Here is a table of magnetic properties for many materials:
http://www.kayelaby.npl.co.uk/general_physics/2_6/2_6_6.html

 

[Dash-IQ]

Here is a table of magnetic properties for many materials:
http://www.kayelaby.npl.co.uk/general_physics/2_6/2_6_6.html

This is absolutely phenomenal, soft iron's coercivity is from 0.20 A/m and hard iron are 45 kA/m.
It's super super easy to magnetize and de-magnetize soft iron, it's as if the energy required to do so is "nothing". haha

Now I understand why we require mind boggling amounts of energy to make some strong magnets. Is to create such powerful field strengths.
Thank you for this.

 

[Dash-IQ]

UltrafastPED, is 1 Gauss = 79 A/m? Is this statement true?

 

[Enigman]

UltrafastPED, is 1 Gauss = 79 A/m? Is this statement true?

Nope. At least not dimensionally...$[G]=\frac{[M]}{[A][t]^2}$
It would be better stated as Magnetic field strength corresponding to 1 gauss is 80 A/m
http://www.wolframalpha.com/input/?i=gauss&a=*C.gauss-_*Unit-

 

[Dash-IQ]

Nope. At least not dimensionally...$[G]=\frac{[M]}{[A][t]^2}$
It would be better stated as Magnetic field strength corresponding to 1 gauss is 80 A/m
http://www.wolframalpha.com/input/?i=gauss&a=*C.gauss-_*Unit-

I'm trying to gain some perspective here, is 160 A/m a strong field? Does a solenoid require a lot of power to create such a field strength? Based on the link you shared(Thanks btw,) the current required to create such a field is 5 A, at 1 cm! Thats a lot of current for such a small wire.

I assume it's something weak, simple to create and a small solenoid with less than a 1W of power can create it. Comparing it with stronger solenoid used to manufacture permanent magnets that consume above 10kW of power to create a highly powerful field.

 

[Dash-IQ]

If H = 160 A/m(2 Oe), is that a lot/strong?