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 Co on Cu(100), Cu(110), and Cu(111) using the magneto-optic Kerr effect. In general, the perpendicular anisotropy in the Fe films is enhanced for growth at low temperature, 80 K. Perpendicular remanence has been 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 inconsistent with standard empirical theories of magnetocrystalline, magnetoelastic, and magnetostatic surface anisotropies and suggest a common magnetic interface anisotropy.