ferrite powder/ magnetite powder difference
ferrite powder/ magnetite powder difference
(OP)
Hi
Please excuse my ignorance, I'm new to magnetic materials and no matter how much reading I do still can't get my head around a few things.
I'm wondering if anyone can clear up the differences in the magnetic properties of magnetite and ferrite powders for me?
Am I correct in thinking that ferrite powder has to be magnetized by applying an external magnetic field whereas magnetite powder does not?
i.e. if a remanence of 140-150mT for a ferrite powder is being quoted, is this after it has been magnetized in an external field?
Would it be possible to detect ferrite powder using a magnetometer if no external magnetic field had been applied first?
Cheers Chris
Please excuse my ignorance, I'm new to magnetic materials and no matter how much reading I do still can't get my head around a few things.
I'm wondering if anyone can clear up the differences in the magnetic properties of magnetite and ferrite powders for me?
Am I correct in thinking that ferrite powder has to be magnetized by applying an external magnetic field whereas magnetite powder does not?
i.e. if a remanence of 140-150mT for a ferrite powder is being quoted, is this after it has been magnetized in an external field?
Would it be possible to detect ferrite powder using a magnetometer if no external magnetic field had been applied first?
Cheers Chris





RE: ferrite powder/ magnetite powder difference
Ferrite is a different iron oxide usually with other materials
If the ferrite powder has not been previously magnetized, then a magnetometer will see only the distortion of the earth's magnetic field caused by the ferrite, but I would think that's a pretty small effect, unless you have a lot of ferrite powder. Even if it's been magnetized previously, unless all the particles were magnetized in-place, you'd probably still only see the field distortion and not a field directly from the powder.
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RE: ferrite powder/ magnetite powder difference
With that low of a remanence this is a magnetically soft ferrite, the kind that is used as cores or chokes. These are meant to nearly transparent to magnetic fields at some frequency, but not at others.
Because it is feromagnetic you will see it with a magnetometer, but how much depends on the frequency and field intensity. If both ate low then I doubt that you would see it.
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RE: ferrite powder/ magnetite powder difference
Ferorite magnet includes hard and soft ferrite. "ferri" means ferrimagnetic, vs ferromagnetic, so the magnetization is relatively low, whne compared with ferromagnetic materials. The remanence of a hard ferrite is normally larger than 200 mT, however, if it is a powder form, the remanence can be much smaller due to lack of anisotropy (possibly) or demagnetization factor.