Magnetic properties of Fe-Cu alloys prepared by pulsed electrodeposition
Résumé
FexCu100−x metastable alloys were prepared by pulsed electrodeposition for 5x85. The Fe-rich alloys crystallize in the bcc structure of -Fe and the Fe-poor ones in the fcc structure of Cu. The magnetic properties of the ferromagnetic Fe-rich alloys x50 are reminiscent of those observed in Fe-Cu alloys prepared by other methods. The Curie temperature decreases regularly with decreasing x. In the Fe-poor alloys x30, the observed properties indicate that Fe-rich clusters form within a Cu-rich matrix. In the x=10 alloy, the Fe clusters are found to be superparamagnetic at room temperature, but a superferromagnetic order develops below a critical temperature of about 120 K. It is suggested that the intercluster coupling is mediated by Ruderman-Kittel-Kasuya- Yosida interactions which are predominantly positive due to the very short intercluster distances.