Talk:Paramagnetism

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Unity[edit]

Is this a phrase: "Paramagnetic materials are attracted to magnetic fields, hence have a relative magnetic permeability greater than unity (or, equivalently, a positive magnetic susceptibility)." Unity what who where? :)

agreed. "greater than unity" is a confusing way of putting it. i have changed it to "greater than 1" --Someones life 04:30, 1 April 2007 (UTC)

and this word: exchanergy what's that? Is that a misspell? :)


Is ferromagnetism a special case of paramagnetism as implied in para 3?--Light current 22:04, 19 September 2005 (UTC)....


Even ferro,ferrimagnetic materials align with an external magnetic field (if it means spontaneous magnetisation in ferromagnetism then the situation is different).

Paramagnetic materials attract and repel like normal magnets when subject to a magnetic field-Wrong statement without proper explanation. Justin

This definition is acceptable from the external link given

The Langevin model, which is true for materials with non-interacting localised electrons, states that each atom has a magnetic moment which is randomly oriented as a result of thermal agitation. The application of a magnetic field creates a slight alignment of these moments and hence a low magnetisation in the same direction as the applied field.


Materials[edit]

Is the list meant to be exhaustive? It doesn't include Titanium, but according to that article it should. --87.82.29.198 19:20, 18 June 2006 (UTC)


How about irradiated crystals and radicals? Example: Irradiated solid alanine, both singel crystals and powder gives an electron paramagnetic resonance (EPR) signal. The organic radical DPPH is used as an EPR reference.

Should they not be included in the list of paramagnetic materials? (Hakgu 15:32, 29 May 2007 (UTC))

Frankly, this is a poor contribution as it stands. Except for oxygen, none of the materials listed exhibit Curie-Law behavior - "iron oxide" (the composition is ambiguous!) is magnetically ordered, and all the metals listed act act like typical paramagnets under no circumstances at all! No expert in magnetism would have selected lithium, sodium, or aluminum as examples of typical "paramagnets" at all. These metals exhibit weak, temperature-independent, Pauli paramagnetism, with room temperature magnetizations that are orders of magnitude smaller even than liquid oxygen. (Anyone ever see aluminum suspended between the pole faces of a small lab magnet?) When I find the time, I'll try to do an extensive rewrite. —Preceding unsigned comment added by Gadolinist (talkcontribs) 14:34, 21 June 2009 (UTC)

Spin glass and mictomagnets[edit]

Spin glass and mictomagnets are not a type of paramagnet 132.234.251.211 06:21, 7 August 2006 (UTC)

Paramagnetic examples[edit]

A few examples are listed as being diamagnetic or ferromagnetic as well. Is that possible? Cmcnicoll 22:57, 12 June 2007 (UTC)

Abstract/Introduction[edit]

The abstract of this article states "...paramagnets do not retain any magnetization in the absence of an externally applied magnetic field."

The introduction seems to contradict that directly, in that it states "...paramagnetic materials have permanent magnetic moments (dipoles), even in the absence of an applied field."

My understanding is that the introduction is incorrect and should be changed to read "paramagnetic materials do not have permanent magnetic moments (dipoles) in the absence of an applied field."

Pazfrater 23:19, 11 August 2007 (UTC)

No, it is correct as written. Even without an external field, a paramagnet has microscopic magnetic moments. However, without an applied field, these microscopic moments are not aligned and the overall magnetization (a macroscopic average quantity) is zero. —Steven G. Johnson 03:09, 12 August 2007 (UTC)
I concur with Pazfrater: the first sentence is in my opinion misleading. Kittel's Introduction to Solid State, chap. 14, states the following: "The magnetic moment of a free atom has three principal sources: the spin with which electrons are endowed; their orbital angular momentum about the nucleus; and the change in the orbital moment induced by an applied magnetic field. The first two effects give paramagnetic contributions to the magnetization, the third one a diamagnetic contribution."
I would change the introduction to read: Paramagnetism is a form of magnetism, similar to ferromagnetism, which originates from the spin and the orbital angular momentum of the electrons.Zaffalon (talk) 23:05, 27 September 2009 (UTC)

Pauli-paramagnetism[edit]

I think it is rather confusing that there is no difference made between localized and itinerant forms of paramagnetism. Many metals are not really paramagnetic in the sense of molecular oxygen because their electrons are delocalized in a band.

Jcwf (talk) 21:44, 27 December 2007 (UTC)

Oxygen paramagnetism affect on distribution on Earth[edit]

My question is: does the paramagnetism of oxygen, in the presence of the Earth's magnetic field affect the distribution of oxygen around the Earth. Also, aside, do colder temperatures at the south pole affect the amount of O3 in the atmosphere during the southern hemisphere winter? Cvgittings (talk) 00:59, 14 June 2008 (UTC)

Connection to MO theory[edit]

Perhaps a stronger connection should be made to MO theory? The 'Relation to electric spins' section contains the following:

The permanent moment generally is due to the spin of unpaired electrons in atomic or molecular electron orbitals (see Magnetic moment)

This could be misinterpreted by those unfamiliar with molecular orbitals:

  • 'unpaired' refers specifically to molecular orbital theory. Electrons may be paired in the valence bond model, yet unpaired in MO theory (eg O2)
  • atomic orbitals are irrelevant, except in the special case of single atoms, in which case the molecular orbitals correspond to the atomic orbital.
  • the page on magnetic moment (even Magnetic moment#Magnetic moment of a molecule also merely says 'unpaired electron' and doesn't provide further clarification.

I added links to Atomic orbital and Molecular orbital. If anyone else was confused by this, perhaps we should do more? --Quantum7 23:54, 19 March 2012 (UTC)