The magnetic properties of nonstoichiometric cobalt ferrite nanocrystals di
ffering by their sizes were investigated by magnetic measurements and Fe-57
Mossbauer spectroscopy. We found that the spin-wave Bloch exponent increas
es with increasing particle size, in agreement with previous studies. Under
a magnetic field of 7 T, we observed that the partial reorientation of the
two ferrimagnetic Fe3+ sublattice magnetizations towards the field directi
on increases with increasing the particle size; we discuss the applicabilit
y of an intrinsic spin canting model as a function of the particle size. An
evaluation of the relative amounts of cobalt and iron in each spinel site
is given. (C) 2001 American Institute of Physics.