Ferrimagnetism vs ferromagnetism

[username327]

Hello All,

I am trying to learn about the diffrerent types of magnetism and would like to know how we can tell the difference between ferri- and ferromagnetism? Are their any measurements which can distinguish unequivocally between the two types?

Thank you for any help

[pallidin]

From: http://en.wikipedia.org/wiki/Ferrimagnetism

In physics, a ferrimagnetic material is one in which the magnetic moments of the atoms on different sublattices are opposed, as in antiferromagnetism; however, in ferrimagnetic materials, the opposing moments are unequal and a spontaneous magnetization remains. This happens when the sublattices consist of different materials or ions (such as Fe2+ and Fe3+).

Ferrimagnetism is exhibited by ferrites and magnetic garnets. The oldest-known magnetic substance, magnetite (iron(II,III) oxide; Fe3O4), is a ferrimagnet; it was originally classified as a ferromagnet before Néel's discovery of ferrimagnetism and antiferromagnetism in 1948 [1].

Some ferrimagnetic materials are YIG (yttrium iron garnet) and ferrites composed of iron oxides and other elements such as aluminum, cobalt, nickel, manganese and zinc.

[username327]

Hello pallidin,

Thanks for the quick reply.

Ok so let's assume we are talking about an Fe-oxide for which we don't have any knowledge of the proportions of Fe3+ and Fe2+ but we want to know which type of magnetism it exhibits. Is there a measurement of its magnetic properties we can make which will differentiate between ferri- and ferro? (I know that by implication ferri => some Fe2+)

Thanks

[pallidin]

Thanks. Wish I had more knowledge on this subject.
Perhaps an expert can jump-in and elucidate.