Finding stabilized coercivity in a study of thickness and temperature dependent Co/Ag/Ge(001) ultrathin films

Epitaxial magneto-optical Co/Ag/Ge(001) ultrathin films were investigated at both room temperature and low temperature. Interesting variations in coercivity as a function of thickness and temperature suggest the existance of interfacial exchange interactions. The operative Ag layers required to inhibit intermixing of Co–Ge alloys from the oscillation of coercivity with Ag film thickness were determined. When the Ag film thickness was reduced to the submonolayer range, perpendicular anisotropy was unexpectedly found. Thus unusual phenomenon can be qualitatively discussed in terms of effective magnetic anisotropy by the contribution of reduced Co layers and by surface magnetic anisotropy.