PERPENDICULAR MAGNETIC-ANISOTROPY IN EPITAXIAL ULTRATHIN FILMS OF FE AND CO ON CU(100), CU(110), AND CU(111)

We report studies of the perpendicular magnetic anisotropy of Fe and C o on Cu (100), Cu (110), and Cu(111) using the magneto-optic Kerr effe ct. In general, the perpendicular anisotropy in the Fe films is enhanc ed for growth at low temperature, 80 K. Perpendicular remanence has be en observed below a critical thickness of about 5-6 ML for fcc Fe(100) /Cu(100), fcc Fe(110)/Cu(110), and bcc Fe(110)/Cu(111). In contrast, a perpendicular remanence has been observed only for fcc Co(111)/Cu(111 ) and not in the as-grown state. These results are shown to be inconsi stent with standard empirical theories of magnetocrystalline, magnetoe lastic, and magnetostatic surface anisotropies and suggest a common ma gnetic interface anisotropy.