Site-specific electronic structures of ferrimagnetic Fe₃O₄ measured by resonant X-ray magnetic scattering

Abstract

Resonant magnetic scattering of circularly polarized synchrotron X-rays has revealed the site-specific magnetic moments at two non-equivalent Fe ion sites in Fe 3 O 4 . The energy-dependent peaks for the 026 and 266 reflections were attributed ferrimagnetically to the e and t 2 energy levels of Fe 3d at the A site, and to the t 2g and e g levels at the B site, respectively, having a sequence of t 2g , e, e g and t 2 in order of energy. This sequence agrees with the local spin-density approximation calculations in the literature [Anisimov, Elfimov, Hamada & Terakura, (1996). Phys. Rev. 54, 4387-4390], in which the spin-down band at the Fermi energy corresponds to t 2g . Resonant magnetic Fourier synthesis reveals the electron densities of the ferrimagnetic moments.

Resonant and non-resonant magnetic scatterings with circularly polarized X-rays: magnetic scattering factor and electron density of gadolinium iron garnet

“…Therefore, if circular polarization experiments are performed in an ideal condition, charge and magnetic scattering factors given by equations (8) and (10), respectively, may be of the same order. In circular polarization experiments of Fe 3 O 4 at the Fe K edge, similar asymmetrical ratios are reported as ÁI/2I = À0.070 for the 266 reflection and ÁI/2I = 0.074 for the 026 reflection (Okube & Sasaki, 2014), in comparison with À6 Â 10 À4 and 1 Â 10 À3 for XMCD (Okube et al, 2012). In summary, the appearance of positive-negativepositive peaks is reminiscent of the ÁI/2I peaks, although the ÁI/2I spectrum is much narrower than the XMCD one in terms of peak width.…”

“…The linear polarization geometry of X-ray scattering allows for the extraction of only magnetic information related to resonant scattering, while circularly polarized RXMS (hereafter referred to as CP-RXMS) produces additional imaginary components in the polarization operator of nonresonant magnetic scattering, allowing for the observation of bonding electrons away from the inner shell of target atoms. Due to the presence of both non-resonant and resonant magnetic scatterings with CP-RXMS, interference with charge scattering occurs, making it possible to examine the electronic structures of magnetic materials Okube & Sasaki, 2014). CP-RXMS that uses both right-and lefthanded circular polarizations has the following features: (i) the interference term includes both resonant and non-resonant magnetic scatterings, which are observable simultaneously (e.g.…”

Site occupancy of Fe2+, Fe3+and Ti4+in titanomagnetite determined by valence-difference contrast in synchrotron X-ray resonant scattering

“…Some applications of the resonant diffraction studies have been reported on valence and charge ordering with similar crystal structures (e.g. Grenier et al, 2002; Palancher et al, Beale et al, 2012;Subías et al, 2012;Okube & Sasaki, 2014).…”