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Unilke normal ferromagnets it is stated here that ferrite (ceramic) or else called ferrimagnets, non-intuitively have a positive temperature coefficient meaning their magnetization decreases with a drop in temperature.

Unlike Neodymium, Samarium Cobalt, and Alnico, Ceramic magnets have a Positive Temperature Coefficient for the Intrinsic Coercive Force (Hci)

Normally you would expect from magnetized matter as temperature falls, sporadic motion of atoms to be dumped down therefore an increase in coherency and alignment of the magnetic domains as temperature drops thus a stronger magnetization of the magnet and magnetic field created at lower temperatures.

What is the explanation and physical process description taking place especially in ceramic (ferrite) magnets that differs from normal ferromagnets and is responsible for this non-intuitive strange behavior?

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We dont actually know.Finding the band structure for ceramics is not easy to do at all and is still in ongoing research so it could be anything.

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  • $\begingroup$ This is a most interesting answer. I did not expect this. Do you have any references of ongoing research on this matter? I myself could not find any answer to this in the literature and thought that this was just a fluke. $\endgroup$
    – Markoul11
    Jan 22, 2022 at 16:12
  • $\begingroup$ Found this interesting link on the subject e-magnetsuk.com/ferrite-magnets/… $\endgroup$
    – Markoul11
    Jan 22, 2022 at 16:22
  • $\begingroup$ In the previous comment link it says: "...However the magnetic output does fall with temperature (it has a negative temperature coefficient of Induction of -0.2 %/degC from ambient). The end result is that Ferrite magnets (ceramic magnets) can be used at high temperature with very few issues." So, they do actually loose magnetism with increase of temperature but because their opposing phenomenon of positive coefficient magnetic coercivity +0.27 %/deg C the net result is +0.07 %/deg C. $\endgroup$
    – Markoul11
    Jan 22, 2022 at 16:37
  • $\begingroup$ Looks to me that two opposing temperature-magnetic effects are taking place simultaneously. Because the macroscopic powder structure of ferrite magnets as temperature increases at the atomic scale the jiggling motion increases leading to a loos of magnetization at the atomic scale but at the same, time increase in temperature acts as fusion of the powder structure of ferrite magnets at the macroscopic molecular scale that increases the bonding forces of the powder particles that results in reduced motion of the magnetic domains and therefore a better alignment and magnetization. $\endgroup$
    – Markoul11
    Jan 22, 2022 at 16:46

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