The Hysteresis Loop of Raw Iron: Understanding Coercivity and Magnetization

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Discussion Overview

The discussion revolves around the hysteresis loop of raw iron, specifically focusing on coercivity and magnetization. Participants explore the properties of raw iron compared to other materials, the implications of coercivity values, and the relationship between magnetic field strength and energy requirements for magnetization.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • Some participants note that the coercivity of raw iron is 2 Oe (160 A/m) and question whether a field of 2 gauss can effectively magnetize or demagnetize this material.
  • There is uncertainty regarding the conversion between gauss and A/m, with some participants suggesting different values and referencing various sources.
  • One participant compares the coercivity of raw iron to that of neodymium-iron-boron, highlighting the significant difference in their coercivity values.
  • Participants discuss the ease of magnetizing and demagnetizing soft iron, with one suggesting that the energy required is minimal.
  • Questions arise about whether 160 A/m is considered a strong field and the power requirements for creating such a field with a solenoid.
  • Some participants express confusion about the dimensional accuracy of the conversion between gauss and A/m, with differing opinions on the correct value.

Areas of Agreement / Disagreement

Participants express various viewpoints on the coercivity of raw iron and the implications of its magnetic properties. There is no consensus on the exact values for conversions between gauss and A/m, nor on the strength of the magnetic field represented by 160 A/m.

Contextual Notes

Participants reference multiple sources for conversion values and magnetic properties, indicating a reliance on external material that may not be universally accepted. There are also unresolved questions about the energy requirements for creating specific magnetic fields.

Who May Find This Useful

This discussion may be of interest to those studying magnetism, materials science, or electrical engineering, particularly in relation to magnetic properties and their applications.

Dash-IQ
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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.
 
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UltrafastPED said:
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.
 
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UltrafastPED said:
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 :biggrin:

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.
 
UltrafastPED, is 1 Gauss = 79 A/m? Is this statement true?
 
Enigman said:
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.
 
If H = 160 A/m(2 Oe), is that a lot/strong?
 

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