Photoemission electronic states and magnetic properties of Dy(Co1−xFex)2

The valence band electronic states of Dy(Co1−xFex)2 Laves phases with x = 0, 0.05, 0.1, 0.7 and 1.0 were measured by the ultraviolet photoemission spectroscopy (UPS) in room temperature. The Curie temperatures were determined from the electrical resistivity measurements and from the temperature dependence of the hyperfine fields by 57Fe Mössbauer spectroscopy. The UPS spectra showed the very pronounced composition dependent emission at the Fermi energy EF, the broad band within 0 and −4 eV binding energy interval below EF and two strong features at about −6.5 and −9.0 eV. The spectra were compared with the band structure calculations using the full-potential linearized augmented plane waves (FLAPW) method. From the comparison we concluded that the intensities at EF are correlated with the values of the Curie temperatures, the broad band comes entirely from different 3d Co and/or Fe states and the strong two features come entirely from 4f electrons of dysprosium.