Experimental exchange-split energy-band dispersions for Fe, Co, and Ni

Using angle-resolved photoemission with single-crystal Fe(111) and Co(0001), we have determined accurate exchange-split energy-band dispersions E(k→) along symmetry lines. For Fe, Co, and Ni, respectively, occupied d-band widths are 3.1 eV (P), 3.8 eV (L), and 3.4 eV (L,A X), while exchange splittings are ∼1.5 eV (P), ∼1.1 eV (Γ), and 0.3 eV (near L). Comparison with theory shows that state-of-the-art ab initio calculations describe the strong ferromagnets Fe and Co much better than Ni. © 1980 The American Physical Society.