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The spin-dependent electronic structure of monolayer coverages of rare-earth metals on Fe(001) has been studied by spin-resolved photoelectron spectroscopy with synchrotron radiation.The highly spin-polarized photoemission from the localized 4f levels of Gd, Tb, and Dy on Fe(001) reveals the antiparallel coupling between these heavy rare earths and the Fe spin moment. Exchange-split final-state multiplet terms of the 4f spectra of the heavy rare earths are explicitly distinguished by direct observation of opposite polarization. For 1 monolayer of the light rare-earth Nd on Fe(001) the rare-earth magnetic moment couples parallel to the Fe magnetic moment.The study of the electronic and magnetic properties of low-dimensional systems has recently attracted considerable interest. Several experimental techniques now provide sensitivity to ferromagnetic ordering for a single atomic layer. This progress now allows an investigation of surface, interface, and ultrathin-film magnetic systems. Ferromagnetism has been unambiguously detected in a few cases for 3d transition metals in the monolayer thickness range. 'Complex magnetic behavior has been reported as a function of the overlayer thickness and temperature. 7 Critical exponents for the two-dimensional magnetic phase transition at T, for one Fe monolayer onAu (100) have recently been determined. s Very little information was, on the other hand, available until now on the magnetic and electronic properties of rare-earth ultrathin films and interfaces. A magneticresonance study revealed a strong temperature-dependent uniaxial perpendicular magnetic anisotropy in epitaxial ultrathin Gd overlayers on W(110). Remanent in-plane ma netization has been observed for Gd overlayers on Fe. " This system offers the opportunity of studying the complex interface exchange coupling between the rareearth overlayers and a magnetic substrate. Spin-resolved Auger-electron spectroscopy measurements" and spinresolved photoemission experiments'o detected antiparallel coupling between the Gd 4f moment and the Fe magnetic moment. Camley'z discussed the magnetic phase diagram of Gd films on a Fe surface as a function of tem-perature and external magnetic fields theoretically.Bliigel'3 studied the electronic and magnetic structure of Gd on transition-metal (001) surfaces and of Gd impurities in transition-metal hosts within a local-spin-density approximation.For both Gd impurities in Fe and a Gd overlayer on Fe(001), antiferromagnetic coupling between the Gd magnetic moment and the Fe magnetic moment is favored. These calculations also predict a reduction of the Fe surface magnetic moment and 3d average exchange splitting due to hybridization of the Fe 3d states with the rare-earth Sd states.In this paper we present experimental results on the electronic and magnetic coupling between rare-earth metals and the Fe(001) surface by spin-resolved photoemission with synchrotron radiation. This work extends our previous investigations on Gd overlayers on Fe(001). 'n The spin-polarized emission of the hi...

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The spin dependence of the electron current absorbed by a thin Fe(001)-film (target current) has been measured as a function of energy in the range (0 ÷ 22) eV above the vacuum level. The peak value of the spin asymmetry is 7% at 11 eV electron energy. The measured energy dependence of the spin asymmetry is in very good agreement with earlier predictions in the framework of a dynamical LEED calculation by Tamura et al.

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