Probing the4pelectron-spin polarization in NiO

Abstract

K-edge resonant x-ray magnetic scattering experiments have been performed on antiferromagnetic NiO. The observation of two resonances at the K edge allows the construction of models to compare the electronic properties of NiO and the observed resonant magnetic x-ray scattering. From the polarization analysis of the scattered beam, a quadrupolar transition (1sϪ3d) and a dipolar transition (1sϪ4p) are identified. While the quadrupolar transition can be modeled using an atomic picture for the 3d electrons, the dipolar transition is associated to a broadband structure of p electrons and its energy profile is compared to electronic bandstructure calculations.

Mechanism of resonant x-ray magnetic scattering in NiO

“…Figure 2 shows I(ω) in comparison with the K edge fluorescence experiment. 4 The solid and the broken lines represent the spectra for V c 4p = 0 and 3 eV, respectively. The attractive interaction enhances the intensity in the low-energy side.…”

“…We analyze the recent experiment of Neubeck et al, 4 paying special attentions to the band effects of the 4p states. In NiO, Ni atoms form an fcc lattice.…”

“…We will show that these couplings actually give rise to the RXMS spectra in agreement with the recent experiment. 4 A caution is to be made on the intra-atomic Coulomb effect; without treating the 4p states as a band, the Coulomb interaction gives rise to too large RXMS intensities. Thus the 4p band effect has a role of reducing the effect of the Coulomb interaction.…”

“…In the RXMS experiment for NiO, the K domain is specified, but the S domains are mixed. 4 For generating the RXMS intensity, orbitals have to coupled to the magnetic order; in the dipolar process, the 4p states have to couple to the 3d states. Since such couplings are usually much smaller than those to the JahnTeller distortion in LaMnO 3 , the mechanism is much subtler than that for the orbital order in LaMnO 3 .…”

Novel mesoscale defect structure on NiO(100) surfaces by atomic force microscopy

“…Its bulk antiferromagnetic nature lends itself to use in coupled layer magnetic storage media [38], [39] and [40] and the magnetic behavior of NiO nanoparticles is suitable for spin valves important in the rapidly developing fi eld of spintronics [41], [42], [43] and [44]. NiO surface properties have been well investigated [19], [45], [46], [47], [48], [49], [50], [51], [52], [53] and [54] and the band structure [55], [56], [57], [58], [59], [60] and [61] and crystallography of the ideal surface [62] and [63] are well-known. The NiO(1 0 0) cleavage plane [45], [62], [63] and [64] can produce, to within reasonable tolerances, well-ordered, stoichiometric substrates although cleaved surfaces have been reported to contain randomly-spaced step defects, approximately 25-100 nm apart, with the step heights in multiples of 2.1 Å, the Ni-O nearest-neighbor distance [52] and [54].…”