Study on Co-Cr alloy cluster assembling process by magneto-optical Kerr effect

Nanometric Co-10at% Cr alloy-cluster assembled films have been produced by a plasma-gas-condensation method, and examined by transmission electron microscopy and the magneto-optical Kerr effect. With increasing the average weight thickness t we found that the Co-Cr clusters coalesce to form a large network. This formation took place more rapidly among clusters with an average cluster size of d = 2.4 nm than with those of d = 4.6 nm. The isolated Co-Cr clusters are superparamagnetic when t<2 nm. With increasing t, the transition from superparamagnet to ferromagnet occurs more rapidly in the system with d = 2.4 nm than in that with d = 4.6 nm, in accordance with their morphological characteristics.