Interpretation of spin-polarized electron energy loss spectra

Article

关键词: FERROMAGNETIC TRANSITION-METALS;    STONER EXCITATION SPECTRUM;    LOSS SPECTROSCOPY;    INELASTIC-SCATTERING;    NEUTRON-SCATTERING;    SELF-ENERGY;    DYNAMICS;    NICKEL;    WAVES;    FE;   

DOI  :  10.1103/PhysRevB.63.014409

来源: SCIE

【 摘 要 】

We study the origin of the structure in the spin-polarized electron energy loss spectroscopy (SPEELS) spectra of itinerant-electron ferromagnetic crystals. For our study we consider a model based on 3d tight-binding energy bands and a multiband Hubbard Hamiltonian. We find it is not the total density of Stoner states that determines the response of the system in the Stoner region, as usually thought, but the densities of Stoner states for only a few interband transitions. Which transitions are important depends ultimately on how strongly umklapp processes couple the corresponding bands. This allows us to show, in particular, that the Stoner peak in SPEELS spectra does not necessarily indicate the value of the exchange-splitting energy. Thus, the common assumption that this peak allows us to estimate the magnetic moment through its correlation with exchange splitting should be reconsidered, both in bulk and surface studies. The above mechanism is also one of the main causes for the typical broadness of experimental spectra. Finally, our model predicts that high-energy spin waves should be excited in SPEELS experiments.

【 授权许可】

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