I am attaching M-H curve. If any more information is needed, I shall do the needful.
Evgeniy V. Kulakov sample is in powder form, mean particle size around 8 micrometer when analysed through Horiba Particle Size Analyzer.
Thanks for suggestion, shall implement in next run.
As per the current loop, coercivity and remanent magnetisation approaches zero, Saturation magnetization 100-150 emu/g, based on it can Superparamagnetism be predicted? Or for analysis and type of magnetization prediction, next run is needed?
Dear Amit,
Can you please tell us what is the difference between the two curves (one in black and the other in red)? The label is not included in the image. Are they two measurements on different samples? Or two measurements of the same sample but at different temperature?
Anyway, taking into account that the curves are not saturated (especially the red one) and that the loops do not seem to exhibit any hysteresis, I would say that you have a SUPERPARAMAGNETIC system.
In order to be sure, you have to perform Zero Filed Cooled-Field Cooled curves, to deduce the blocking temperature.
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Indeed, without knowing anything about the sample, the first guess is superparamagnetism. Since the particule size is 8um, that implies any grain consists of varius magnetic grains, since one would expect the superparamagnetic length-scale more like 1-10nm.
Otherwise, it might be a very bland ferromagnet, with very small coercivity.
As suggested, looking at the M(T) temperature dependence after field cooled and zero field cooled, playing with the field of measurement (10 Oe, 1kOe, etc) should help
If, as expected, these curves are recorded at low temperatures, and according to the mentioned grain size, the behavior exhibited is a superparamagnetic (almost zero coercivity). However, it is really odd that such large magnetization and such large grain size are combined with superparamagnetism.
As @Norbert. M Nemes pointed out, those 8 micron grains detected by the Particle Size Analyzer must be made of much smaller magnetic grains, in order to exhibit superparamagnetism. For instance, they may be composed of magnetic nanocrystals embedded in a non-magnetic matrix.
I expect the superparamagnetism behavior to happen at lower particle sizes. Although, it was mentioned that the mean particle size is about 8um, there may be some percentage of smaller particle sizes that can exhibit superparamagnetism in the whole batch. It would help if the researcher gives more information about the powder composition under test. Also ZFC measurements on the M(T) curve could shed more light. I am curious to see where the blocking temperature falls. One last question, at what temperature where these M(H) curves obtained (are these done at the room temperature or lower temperatures)?
I believe that this is a dilute ferro- or ferrimagnetic system (possibly a composite, among others in amorphous-nanocrystalline form) in a superparamagnetic state, or a magnetically soft substance with extremely low coercivity and residual magnetization. For a more detailed explanation of the nature of the observed phenomena, it is necessary to perform additional studies proposed above.
hey all and especially Alexander T. Morchenko
How can we differentiate between the M-H curves of SPM and soft magnet if both cases have very small hysteresis (Hci ~ 0, Mr ~ o) without any other measurement
Dear Mohammed,
It may be worth making the same measurements at different temperatures
Dear Morchenko,
Thanks a lot for response
Of course temperature dependence measurement can do that, so I have one more minor inquiry:
What about the saturation magnetization and the saturating field? do these factors make difference?
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