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Thread: Ferromagnetic material

  1. #1 Ferromagnetic material 
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    When an external electromagnetic field is applied to a ferrous material, why and how does the material orientate itself in the electromagnets direction?

    I tried reading this: http://en.wikipedia.org/wiki/Ferromagnetic , but their explanation did not do much for me (I did not understand it).

    I simply learned in school that the electrons point in the direction of the applied field, but there is much more to it than this that I want to understand.


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  3. #2  
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    You are right. The property of ferromagnetism comes from the crystal structures of certain substances and the property of forming domains.

    A domain, in simple terms, is a group of atoms (or molecules for compounds) having dipole moments in a single direction. Many such domains exist in a ferromagnetic crystal. under normal conditions, the dipole moments of all domains cancel out. but under the influence of a magnetic field, they all allign in one direction (that of the field) and the resultant moment is along the applied field. this causes ferromagnetic materials to be strongly attracted to magnets.


    Beyond Equations,

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  4. #3  
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    So then magnets and materials like iron behave the same way when they are exposed to a magnetic field, in that the crystal domains align? Does this have anything to do with electrons individually aligning?
    Of all the wonders in the universe, none is likely more fascinating and complicated than human nature.

    "Two things are infinite: the universe and human stupidity; and I'm not sure about the universe."

    "Great spirits have always found violent opposition from mediocrities. The latter cannot understand it when a man does not thoughtlessly submit to hereditary prejudices but honestly and courageously uses his intelligence"

    -Einstein

    http://boinc.berkeley.edu/download.php

    Use your computing strength for science!
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  5. #4  
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    OK, explain to me what you think electrons are.
    Beyond Equations,

    Pritish
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  6. #5  
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    I was here studying how the MRI works and I got curious about that concept of electron versus dipole alignment. We usually associate an alignment with a sphere-like particle’s axis direction. But with quantum physics knowledge we now know that’s not how subatomic reality really works. My question on this matter is: how can we see magnetism through a quantum reality?
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  7. #6  
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    Its only that I am confused about this; do the electrons themselves align to an externally applied magnetic field, or is it only the domains that align, in which the parallel electron sectors were previously formed due to other circumstances? It seems that the domains only align because of an external magnetic field, while the electrons align because of the Pauli Excursion Principle. "however, they tend to align in the same direction because of the Pauli principle: two electrons with the same spin cannot also have the same "position", which effectively reduces the energy of their electrostatic interaction compared to electrons with opposite spin." -Wiki If electrons cannot have the same position, then wouldn't it be detrimental to their argument that alignment is due to this in that north and north, south and south poles aligning would be the same position and therefore defy the Pauli principle? I must be misunderstanding their explanation.
    Of all the wonders in the universe, none is likely more fascinating and complicated than human nature.

    "Two things are infinite: the universe and human stupidity; and I'm not sure about the universe."

    "Great spirits have always found violent opposition from mediocrities. The latter cannot understand it when a man does not thoughtlessly submit to hereditary prejudices but honestly and courageously uses his intelligence"

    -Einstein

    http://boinc.berkeley.edu/download.php

    Use your computing strength for science!
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  8. #7  
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    Electrons have neither head no tail that can tell us whether they are aligned or not. :-D

    You will learn in later years of your study that electrons cannot be explaiey have no clear 'orbits' around the nucleus. Electrons are explained only by probabilities.

    In an atom, instead of orbits, there are orbitals. Orbitals are the regions around the nucleus where the probability of finding an electron is highest inside the atom.

    Each orbital can hold a max of 2 electrons, both having opposite spins. If an orbital has only one electron, it has a net dipole moment. each atom with such partially filled orbitals has a dipole moment, which aligns and not individual electrons.
    Beyond Equations,

    Pritish
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