Hi! Need help=(

Just noticed a small difference in B-H curve of FeOx nanoparticles placed in paraffin and polymer glue. In particular, coercivity increased(in superparamagnetic particles) in glue comparing to paraffin.

 

For me it sounds quite crazy and it appears to ruin the precision of measuring B-H curve of particles.

 

Measured using VSM.

 

So the questions are - is it normal? How can one predict this effect? Or the VSM needs verification? Thanks in advance.

Edited October 22, 201312 yr by teurgo

I expect no magnetic effect of the matrix materials cited (some very special polymers are ferromagnetic).

 

Possible effect: one matrix material has left some magnetic particles touching an other while the other separates them well. For instance if the surface tension differs, or their viscosity. Your nanoparticles are permanent magnets, aren't they? Paraffin has allowed them to stick closer to an other.

 

Other effect: the organic materials have reduced a little bit of the oxide at the particles' surface. Not equally much by both matrices.

 

Or: different casting temperatures have acted differently on the FeOx.

Thanks! Of course i dont expect too.

 

My particles are too small to have more than one domain.

 

Guess that the best way to check first effect is to make lots of samples with different concentration of particles. For second - add more materials as matrixes. Third - try to warm glue b4 hardening.

 

It is a lot=\ going to find some information first, will be grateful if someone helps.

Edited October 23, 201312 yr by teurgo