Polar Kerr-effect observation of perpendicular surface anisotropy for ultrathin fcc Fe grown on Cu(100)
The predicted perpendicular surface anisotropy is observed for ferromagnetic fcc Fe/Cu(100) via in situ, polar Kerr-effect measurements. Square hysteresis loops are obtained for films 1.5 to 5.7 monolayers thick for 100-K growth. The region of stability of the perpendicularly magnetized state as a function of growth temperature and film thickness is delineated. Combined longitudinal and polar Kerr-effect measurements show that the anisotropy reverts to being in plane for films thicker than approx.6 monolayers.