Magnetic ordering of Cr layers on Fe(100)

The magnetic ordering at the surface of epitaxial Cr overlayers on Fe(100) is studied by spin-polarized electron-energy-loss spectroscopy. The exchange asymmetry oscillates with the thickness of the Cr overlayer with a period of about two atomic layers, proving directly that the surface Cr layer has a net ferromagnetic moment and that successive layers order antiferromagnetically. The exchange asymmetry is predominantly due to spin-flip scattering. The spin-flip spectrum broadens toward lower energy with increasing thickness, suggesting that Cr may have a surface-enhanced magnetic moment. © 1992 The American Physical Society.