Observation of Spin-Polarized Electron Levels in Ferrites

Measurement of spin polarization of photoelectrons from F${\mathrm{e}}_3$${\mathrm{O}}_4$ (MAG) and ${\mathrm{Li}}_{0.5}$${\mathrm{Fe}}_{2.5}$${\mathrm{O}}_4$ (LIF) up to $\hslash \omega =11\mathrm{}$ eV shows that $B$-site $3d$ levels are higher in energy than $A$-site $3d$ levels. In MAG, unpolarized $2p$ electrons are not emitted up to 11 eV. Existing energy diagrams of MAG do not agree fully with the results. As a direct consequence of Hund's rule, the polarization spectra of MAG and LIF are very different because of the presence of ${\mathrm{Fe}}^{2+}$ in MAG.