I have prepared Y2NiMNO6 nanoparticle and did magnetic measurements. From M-T , it follows as literature,i.e , ferromagnetic below 70 K , and paramagnetic above 70K but but surprisingly from M-H plot at 300 K , the plot look like paramagnetic but it has certain coercivity. Can anyone explain what could be the reasons behind it?
I am attaching the plots.
It may not be coercivity, just an experimental artefact. I presume it dc measurements with sufficiently enough data points in the plot?
Yes , It is dc magnetization with sufficient data points around (700). But we have carried out other experiments where paramagnetic plot was linear with no coercivity.
The hysteresis of the M Vs T curves clearly shows that you have the formation of magnetic clusters with a blocking temperature of 75K. However it seems for M Vs H curves that a very weak ferromagnetic component remains up to 300K. The origin of this weak ferromagnetic component may be coming from a secondary phase or to the fact that some clusters are not blocking due to a size distribution i.e. not all the clusters have the same size.
Best regards,
Pedro
I think XRD pattern of your sample should confirm the single-phase nature of your sample. The observed coercivity might origin from the presence of other phase(s).
We have done the XRD analysis. It showed single phase nature. Although the sample is nanorod in nature.
Perhaps, the second phase is present in the sample as an amorphous interlayers (matrix) and is hidden in the XRD picture in the form of some background.
I'm not familiar with this very compound, but its room temperature M(H) loop doesn't look like the one originating from paramagnet. It is too straight, something like this does not happen for paramagnets in so wide field range as shown. Additionally, the coercivity is far from zero, far beyond experimental uncertainties. Smells rather like antiferromagnet (canted?) for me. Mn ions "like" antiferromagnetism. But the up-shifting of the entire hysteresis loop and singularities at zero exciting field are even more intriguing. Are those curves really discontinuous? Is this material conductive? If so, then eddy currents may be the reason for the difference between ascending and descending part of hysteresis loop.
The shift of the loop can be caused by the features of the experimental method (hardware function).
What equipment and method were used for your measurements?
The coercivity is excessively large for a para- or superparamagnetism.
We have used 15 T VSM for measurment. Actually there was no such holder per se because the sample mounting was similar to QD SQUID sample mounting. Sample was placed inside a non magnetic hollow tube.
It is in powder form. Thank you very much for your suggestion but unfortunately we do not have Hall measurement facility around us so we have to think for any other option.
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