In Magnetic measurements., VSM parameter results are given following with Ms = 2.5110 x10-3 emu/g ; Mr = -4.0825 x10-3 emu/g and Hc = 477.34 G. Can anyone import your advice.
It seems that you have a shift along the field axis and at the same time a shift along the magentization axis. A shift can be introduced e.g. by an antiferromagnet/ferromagnet interface (called exchange bias).
Can you provide some more information about your sample? What kind of material/combination of materials/geometry/... is it?
Dear Dr. Aladin., VSM measurement for pure inorganic compounds with imidazole ligands. Thankful for your comments with exchange bias.
Did you make sure that your sample is fully saturated at 9000 Oe? If your sample is not fully saturated, you may have only measured a minor cycle. Minor cycles can be shifted in any directions, depending on the history of the sample.
Does your VSM have a superconducting magnet? Another thing that can explain your shift may be the presence of residual magnetic fields in your magnet. Some magnetic flux sometimes get trapped in superconducting magnets and can polarize your sample (the zero point is biased). Usually the value and the direction of that residual field depend on the magnetic history of the magnet.
See, please also discussion
https://www.researchgate.net/post/What_is_reason_for_negative_saturation_magnetization#view=58638859cbd5c2f5d57d9a65.
Maybe this will help.
Hi Raj,
I always believe that when you see unusual behavior you should first make sure the data are sound before interpreting and categorizing the same. So, some more details would be useful.
It looks like you measured an initial magnetization curve (from a demagnetized state to saturation). Is this correct? If so, the shift that you see is most likely some form of instrument drift. The initial curve should always start from ~0 (depending on how well demagnetized the sample is) and should lie in-between the upper and lower branches of a saturated sample.
Can you tell us a little about the machine that you used? As asked before, is it a SQUID VSM?
Also, some more info about the sample would be useful. Some more details on the material. Also, you mass normalize the moment (to give magnetization), but what is the raw saturation moment and how does this compare to the sensitivity/noise level of your VSM?
Hope this all helps
Greig
Dear Professor,
My hints : In complexes series of work changes with minor ancillary ligands. I got good deceasing results in magnetism. When i go this sample gives very low ferromagnetic property in VSM at RT, but MH loop missing in SQUID at (300,80,40 K).
VSM measured from Lakeshore - 7404 results at room temperature (already attached in question).
But lately i record the same in SQUID (quantum design) which i attached now. Pleased to educate me...
Can you plot your 300K Lakeshore VSM and SQUID results together? The SQUID data should be of higher quality .
What was the mass of the VSM sample?
Dear Raj,
There are a number of additional considerations that need to be answered for clarification of the truth.
For example, reasonable questions were asked by Greig A. Paterson and Aladin Ullrich about mass and geometry of the sample. It is also necessary to consider the remark by Alain Truong on reaching the state of saturation. The shift of loop may be due to exchange anisotropy (two-phase sample FM\AFM) and calibration of the device. Other reasonable questions relate to the aggregate state of sample: powder, solution or solid. In the latter case, the role plays geometry of the experiment: the shape and size of the sample and its orientation relative to the direction of the external field. Did You consider the demagnetizing factor (adjustment of loop taking into account the demagnetizing field)? Are you sure that Your sample is single phase? Maybe Your curves are a superposition of the contribution of the different phases. How did you find that Ms
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