I am planning to carry out M-H and FC and ZFC (M-T) measurements of superparamagnetic iron oxide nanoparticles. For M-H, I am using 2 T field but for FC and ZFC, I am using 50 Oe. My plan is that- First, I will carry out M-H at 300K using 2 T field and stop the field. Without field ( H=0 T), I will cool it to 20 K. At 20 K, I will apply 2 T field for M-H measurement. After this, I will decrease the filed to 50 Oe and take ZFC measurement from 20 K to 300K. But I have a doubt that if 2 Tesla field will affect the orientation of freezed spin at 20 K or not. Will it be different from applying only 50 Oe or not? Or I should warm it to 300K after M-H measurement at 20K and cool it again at H=0T, then apply H=50 Oe for ZFC from 20 K to 300K? I would be grateful to you all for your help. Thank you so much.
Hi Bibek,
Do take a look at this paper if you have not done so already: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1885366/
(and other examples from these authors) as they explain their protocols clearly, and ensure the magnetic history of the particles is appropriately managed when undertaking protocols involving high fields and also ZFC and FC measurements.
Good luck!
Joanna
Dear Bibek Thapa, as a general rule, I would suggest to first make all measurements at LOW fields, to avoid any persistent orientation in your sample. In case of ZFC-FC and M(H) curves, the former should be recorded firts, leaving the M(H) as the last measurement. And, if you plan to perform M(H) above and below freezing temperature, I would suggest to record the curves from high to low temperatures.
Hope this helps.
Dear Joanna,
The paper you provided has several information that I need. Thank you so much.
Dear G. F. Goya,
You are right. Thank you so much for your valuable suggestion.
Thanks Bibek - I'm glad you found the paper helpful. Kind regards, Joanna
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