Magnetic circular dichroism in x-ray resonant Raman scattering in perpendicular geometry from CoFe2O4 and Co metal:: A comparison of valence and inner-shell channels -: art. no. 174435

We present results on resonant Raman scattering (RRS) in perpendicular geometry excited with circularly polarized x rays at the Co L-3,L-2 edges in CoFe2O4 (Co ferrite) and Co metal. In this geometry the incident x-ray beam is perpendicular to the magnetization and the magnetic dichroism is only present in the RRS and not in the absorption. We compare the 3s-RRS channel terminating in an inner shell 3s hole and extra 3d electron (2p(6)3d(n)-->2p(5)3d(n+1)-->2p(6)3s(1)3d(n+1)) and the 3d-RRS channel ending in a 3d electron-hole pair (2p(6)3d(n)-->2p(5)3d(n+1)-->2p(6)3d(n)). The work is based on the measurement of the spectra vs the incident photon energy and integrated over the scattered photon energy. In both samples the dichroism of the inner-shell channel is about an order of magnitude larger than that of the valence channel. The result is explained by a theory based on the fast-collision approximation. We show that this theory provides a general way to choose the optimum scattering channel in the study of magnetic dichroism in perpendicular geometry. The impact of the results is briefly discussed.