Element-specific magnetization of a Gd-Co composite system using spin-polarized Auger electron spectroscopy

Spin-polarized Auger electron spectroscopy is found to have applications for monitoring element-specific magnetization in composite systems. Here, we report on an application of such a study performed on a Gd-Co composite system. Special emphasis is given for $4d$-core-hole-initiated Auger decays in Gd interacting with a Co subnetwork within the energy region of 30--150 eV. Prominent resonant (4→d4f) and nonresonant Auger lines involving 4d(N₄₅), 5s(O₁), 5p(O₂₃), 4f(N₄₅), and (5d,6s)(V) valence states are identified with the information obtained on either the spin polarization spectrum or the corresponding Auger spectra. Besides the applicability of this technique in this system, it is observed that the $5d$ states have enhanced spin polarization, confirming the coupling of moments in the composite system via $5d$ states of gadolinium. It is also directly observed that Co magnetic moments are indeed aligned antiparallel to the Gd ones, as has been postulated by theory and indirectly determined by various methods.