SPIN-POLARIZED PHOTOEMISSION-STUDY OF EPITAXIAL GD(0001) FILMS ON W(110)

Surface magnetic properties of epitaxial Gd (0001) films grown on W (1 10) were studied with spin-polarized resonant 4f photoemission. Films grown at room temperature and subsequently annealed to 550-degrees-C s how 66% polarization at 150 K, whereas films grown at 400-degrees-C sh ow only 46% polarization. Both types of films exhibit surface enhanced magnetic order, with the highest observed surface critical temperatur e exceeding the bulk value by as much as 60 K. For the first time, a r ich variety of novel surface magnetic phenomena, i.e., sizeable perpen dicular polarization component and unusual temperature hysteresis in t he spin polarization, are observed, demonstrating that surface magneti c reconstruction is present in Gd(0001) films.