Does the Magnetic Fluids have a Curie point ?


Dears,

I'm using a kind of Magnetic Fluid Fe3O4 for some heating experiment,
with the nano particles size of 10-20nm.
One question puzzling me is, as a kind of ferromagnetic substance, the
Fe3O4 has a curie temperature above 800 celsius degree. But in
nanosize of 10-20nm, it maybe already under the critical size of
superparamagnetic status for Fe3O4 (~16nm)=EF=BC=8C so, in the
superparamagnetic status, does the Fe3O4 still have a Curie Point ?

Another questions, what is the main factrors or mechanism
for the nano particles in superparamagnetic status to be heated in an
alterating magnetic field ?


Wating for your help, thanks=20

Wang


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