Spin-glass behavior in a fine particle system

A study of the magnetic behavior characteristic of a spin-glass, which has been examined for systems of ultrafine particles, is reported. The results obtained support the suggestion of E. P. Wohlfarth (1977) that spin-glass effects could arise from the clustering of impurity spins in the host material into ferromagnetic rich clusters. All the results are explained on the basis of the Neel superparamagnetic (blocking) model. The results obtained show that the behavior of fine particle systems is similar to that of certain spin-glass alloys (e.g., Au/Fe alloys). This result supports the idea that spin-glass alloys can be interpreted on the basis of a blocking model.