I. Navarro et al., FERROMAGNETIC INTERACTIONS IN NANOSTRUCTURED SYSTEMS WITH 2 DIFFERENTCURIE TEMPERATURES, Physical review. B, Condensed matter, 53(17), 1996, pp. 11656-11660
We study the exchange interactions between ferromagnetic grains disper
sed in a paramagnetic amorphous matrix. This interaction becomes very
important for high-density packing of the grains and also when the amo
rphous matrix is near its Curie temperature. We obtain analytical resu
lts based on a mean-field approximation and also perform a Monte Carlo
simulation. We use both procedures to estimate the ordering temperatu
re as a function of the effective intergrain separation. The theoretic
al predictions are compared with experimental results for the Fe77B18N
b4Cu nanocrystalline alloy.