SPIN-DEPENDENT SURFACE TRANSMISSION IN 3D METALS - IMPLICATIONS FOR MAGNETIC-DICHROISM MEASUREMENTS OF THE VALENCE BANDS

The interpretation of measurements of magnetic dichroism in angle-reso lved photoemission from the valence bands of 3d ferromagnetic metals i s complicated by the simultaneous presence of spin-dependent surface t ransmission of the spin-polarized photoelectrons into the vacuum. As a result, two separate mechanisms contribute to the change in the photo emission intensity spectra when the sample magnetization is reversed. The magnitude of the surface transmission effect in the ''light'' 3d m etals has been measured using Cu(001) as a sample, and an intensity as ymmetry of +/- 3% has been found. This is smaller than, but approximat ely the same size as, the magnetic dichroism measured for iron and cob alt, and demonstrates experimentally that neither mechanism can be gen erally neglected in favor of the other.