I have one hexaferrite with a particular saturation magnetization value. When I made a composite of this hexaferrite with graphene the saturation magnetization of the composite becomes higher than that of hexaferrite at room temperature. Why this is so? Anyone know?
The observation is somehow surprising but very interesting. Since graphene itself is not a magnetic material, the enhancement observed (if it reproducible) appears to result from the interactions between the two components in composite. However, your question seems not to be detailed enough. Which form is haxaferrite in (nanoparticle or compound)? How did you combine haxaferrite to graphene, chemically covalent bonding or just physical adsorption? How reproducible is the observation?
The hexaferrite is M-type prepared through chemical coprecipitation method. To prepare the composite we have prepared the precipitation in presence of graphene and then thermal treatment was done.
Is there any scope to explain this phenomena with the room temperature ferromagnetism of graphene?
If there is no phase separation of ferrite during synthesis of the composite? It is possible that the phases are formed with the magnetization greater than the magnetization of hexaferrite. XRD phase analysis can clarify the matter.
Technically YES.Many reasons:: 1. Impurities, 2. Reshaping grain boundaries of the domains, 3. Type of graphene you have with the type of bonds it is with your material. etc. etc. Pure graphene is diamagnetic however RGO might be ferromagnetic at RT. Please find out how the graphene is attached to ferrite. Also when you compare, make sure you have the same conc of ferrite in both the cases.
@Akshaya Swain..
Sir, can you clarify your third point please? If it is chemically attached (May I confirm it through XPS analysis?) or physically adsorbed on the graphene surface what will happen in each case? One thing is that I have modified the graphene by using mixed acid before using it and it is confirmed that after modification graphene contains many oxygenated functional group, so, room temperature ferromagnetism can happen here?
XPS would also give different bond types and corresponding ratios. Why don't you try FTIR which will confirm all kinds of bands you have in the material. Magnetism can change whether you have Physical or chemical adsorption. Because the pi-electron systems have lot of free electrons. Also if you have used reducing agents like hydrazine or if there is any N- fuctionalization then it contributes a lot due to lone pair of electrons on it. You can check whether your method of preparing RGO is magnetic or not with similar conditions/compositions without ferrite. You may also compute the ferrite amount in the composite and how much of it is suppressed by RGO.
That means Free electron can change the magnetic property. Is it? How?
How can I calculate the ferrite amount present in the final material?
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