Sequential deposition and metastable states in rare-earth/Co films

A study of the structural and magnetic properties of sequentially deposited (multilayered) sputtered films of Gd and Co is presented. It is found that by varying the deposition temperature, the film composition, and the multilayer sequences the film morphology can be controlled in a continuous way and, thus, new magnetic structures achieved. In particular, samples deposited at ambient temperature (80 °C) show clear evidence of layering and have fairly simple magnetic properties. On the other hand, at elevated deposition temperature (380 °C) no evidence of layers is seen, but one finds a pronounced chemical reaction which results in the formation of ${\mathrm{GdCo}}_2$ in all cases where the nominal composition is on the Co-rich side of ${\mathrm{GdCo}}_2$. It is demonstrated that one can take advantage of this reaction and use the multilayer sequences to control extrinsic properties of the films such as coercivity.