Q about diff. between ferro and paramagnetism under a strong mag field

In summary, ferromagnetic materials have domains with mostly parallel magnetic dipoles, while paramagnetic materials do not have domains. Under a magnetic field, domains in ferromagnetic materials align and grow, while in paramagnetic materials, the dipole moments align with the field. Having domains in a material does not necessarily make it better for magnetization and can actually make it worse. To achieve strong magnetization, the domains in a ferromagnet must be eliminated.
  • #1
parsa418
25
0
Hi
From what I understand ferromagnetic materials have domains that contain magnetic dipoles that are almost all parallel to each other. However these domains have random directions.
Under a magnetic field the domains in the ferromagnetic material that are magnetized in the field direction grow and the domains that aren't shrink.
However, in a paramagnetic material there are no domains. Under a magnetic field a lot of the dipole moments of a paramagnetic material become parallel with the field.
My first question is what makes having domains in a material better for magnetization?
My second question is under a strong magnetic field shouldn't both paramagnetic materials and ferromagnetic materials become equally magnetized because eventually all the dipole moments of both materials become parallel with the magnetic field? (is saturation magnetization related to this?)
Any help will be much appreciated
Thank you
Parsa
 
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  • #2
Hi Parsa! :smile:
parsa418 said:
My second question is under a strong magnetic field shouldn't both paramagnetic materials and ferromagnetic materials become equally magnetized because eventually all the dipole moments of both materials become parallel with the magnetic field? (is saturation magnetization related to this?)

I think it's only a question of degree …

both para and ferro depend on the exchange interaction (see http://en.wikipedia.org/wiki/Exchange_interaction), and if it's strong enough you get ferro, see http://en.wikipedia.org/wiki/Paramagnetism#Relation_to_electron_spins …
"If there is sufficient energy exchange between neighbouring dipoles they will interact, and may spontaneously align or anti-align and form magnetic domains, resulting in ferromagnetism (permanent magnets) or antiferromagnetism, respectively."​
My first question is what makes having domains in a material better for magnetization?

No, domains make it worse …

to produce a strong ferromagnet, we need to eliminate the domains! :wink:
 
  • #3
Thank you tiny-tim. Sorry for the late reply. I was travelling.
 

Related to Q about diff. between ferro and paramagnetism under a strong mag field

What is the difference between ferromagnetism and paramagnetism?

Ferromagnetism is a phenomenon where certain materials, such as iron, nickel, and cobalt, have a permanent magnetic moment even in the absence of an external magnetic field. This means that they can be magnetized and retain their magnetization after the external field is removed. On the other hand, paramagnetism is a weaker form of magnetism where the materials only exhibit magnetic properties when placed in an external magnetic field.

What happens to the magnetic properties of a material under a strong magnetic field?

Under a strong magnetic field, the magnetic properties of a material can change. In the case of ferromagnetic materials, the strength of their magnetization increases, while in paramagnetic materials, their magnetic moments align with the external field, making them more magnetic.

How does temperature affect ferromagnetism and paramagnetism?

Temperature plays a significant role in determining the strength of ferromagnetic and paramagnetic materials. As the temperature increases, the strength of ferromagnetism decreases, and eventually, the material loses its magnetic properties. In contrast, the strength of paramagnetism increases with temperature, but at a slower rate compared to ferromagnetism.

Can ferromagnetism and paramagnetism coexist in a material?

Yes, it is possible for a material to exhibit both ferromagnetic and paramagnetic properties. This is known as ferrimagnetism, where the material has a net magnetic moment due to the presence of both ferromagnetic and paramagnetic ions.

What are some examples of ferromagnetic and paramagnetic materials?

Some examples of ferromagnetic materials include iron, nickel, cobalt, and their alloys, while examples of paramagnetic materials include aluminum, platinum, and titanium. However, it is important to note that the magnetic properties of a material depend on its composition, structure, and temperature, and not all materials within these categories will exhibit the same level of magnetism.

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