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Do orbits in diamagnetic materials align to external magnetic fields?

  1. Apr 21, 2014 #1
    Hi, I am having a question about diamagnetism. I understand that ferromagnets realign with external magnetic fields. I know that besides diamagnets like copper, bismuth, that all matter exhibit some diamagnetism to some degree. I wonder though if these paired electron filled orbits of diamagnets realign with the external magnetic field? This seems like very simple self explained question since, how other wise diamagnetism would be formed?. But, I am not 100% sure that I understand this correct?

    So , do the electron spin and electron orbits of diamagnetic materials like copper realign to magnetic fields?

    Best Regards
  2. jcsd
  3. Apr 21, 2014 #2

    Simon Bridge

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    All materials with a magnetic moment will experience a torque in applied magnetic fields.
    Do you know how diamagnetism works?
  4. Apr 22, 2014 #3
    Hi, yes but diamagnets have a zero net magnetic moment, electrons are paired. still there is still a small eddy current like effect with the paired electrons left when an external magnetic field is applied so the magnetic field of an ordinary stationary magnet respells diamagnets a the paired electrons are both accelerated and braked in their orbits. Anyway, I was wondering if the imaginary orbits also realign in diamagnets just like ferromagnets. I am just not sure.
  5. Apr 22, 2014 #4

    Simon Bridge

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    Well - a perfect diamagnet expels all external fields - i.e. a superconductor.
    So the question doesn't mean anything in those terms.

    Note: metals exhibit diamagnetism but the free electrons are not localized to orbitals.

    I think you need to revisit the theory:
    ... reasonable start.
  6. Apr 22, 2014 #5
    thanks, I will see :)
  7. Apr 24, 2014 #6
    I am trying to understand this, as I am reading as much I can, but I have to really understand one thing first, it would be so helpful to know so with fear of getting out of topic :

    The electron can only have two spins only as it orbits around the nucleous. If we apply a magnetic field on an unpaired electron (say in a non conductor so the electron is bound to the orbit), the electron spin will reorient only either up or down to the external magnetic field( and yes as it precess around the field).
    Now, without external magnetic fields. since the electron orbit is basically "an external magnetic field" the electron should either always and only spin parallel or anti parallel to the orbit. Do I understand this part correctly? if my point isnt clear here is a simplified question:

    An electron orbit is occuring on a plane of x,y, this electron is always and only spinning as well in the same x,y plan of the orbital regardless if the spin is up or down. So, Is the electron spin plane always the exact same as the orbit plane of the same electron?

    Last edited: Apr 24, 2014
  8. Apr 25, 2014 #7


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    The orientation of the spins doesn't change in diamagnetic compounds. In the simplest case, a Helium atom, the spins are paired into a singlet and the question about the orientation of the spins makes no sense. Rather under the perturbation of the magnetic field, the s-orbitals admix some contribution of functions with higher angular momentum - namely p - so that they accquire some magnetic moment.
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