Magnetic properties of Co/Ge(111) films: Effects of growth temperatures

Effects of growth temperatures to the magnetic properties of Co/Ge(111) ultrathin films have been studied. For 22 monolayers Co/Ge(l 11) deposited at 200 and 300 K, the difference of the temperatures where ferromagnetism disappears upon annealing treatment is about 75 K. The Co/Ge interface shows a more ordered structure for films deposited at 200 K as revealed by low-energy electron diffraction measurements. The responses of magneto-optic signals could be explained by the different morphologies at the interfaces. A Co/Ge(111) system exhibits a strong in-plane anisotropy that is not altered by the interfacial conditions.