X-ray absorption and emission spectroscopy study of Mn and Co valence and spin states inTbMn1−xCoxO3

Abstract

Abstract.The valence and spin state evolution of Mn and Co on TbMn 1-x Co x O 3 series is precisely determined by means of soft and hard x-ray absorption spectroscopy (XAS) and Kβ x-ray emission spectroscopy (XES). Our results show the change from Mn 3+ to Mn 4+ both high-spin (HS) together with the evolution from Co 2+ HS to Co 3+ low-spin (LS) with increasing x. In addition, high energy resolution XAS spectra on the K pre-edge region are interpreted in terms of the strong charge transfer and hybridization effects along the series. Disorder and competitive interactions lead to a magnetic glassy behaviour in these samples.

Interplay of local structure, charge, and spin in bilayered manganese perovskites

“…the intensity of p2 decreases with decreasing the number of empty states in 3d orbitals. In our case the intensity of p2 feature increases with doping, particularly for x=1 sample containing formally Mn 4+ ions, which is in agreement with interpretation suggested by Cuartero et al 26 In order to obtain more quantitative understanding of the pre-edge doping evolution we estimated the p2 intensity, taken as the maximum from the experimental data (Fig.5a) as well as maximum and area from the data fits (see the supplement 15 and supplementary Fig.5). In Fig.5a we also show the dependence of the probability of finding different number of Mn 4+ ions as neighbors of given absorber (Mn ion) calculated from a binomial distribution.…”

“…from 1s to the 4p character of the 3d-band of the excited ion for geometry with broken inversion symmetry and non-local i.e. to a 3d states of neighboring metal sites through the oxygen mediated intersite hybridization Mn(4p)-O(2p)-Mn'(3d) 21,26 . It has been suggested that this non-local contribution appears at a higher energy since such a final state is also more delocalized and thus it is less affected by the core hole potential 21,26 .…”

“…Recent HERFD-XANES study on TbMn 1−x Co x O 3 showed two well resolved features in the pre-edge region at energies corresponding to p1 and p2 and it has been concluded that p1 shows both dipole and quadrupole contributions while p2 can be assigned mostly to the nonlocal dipole transition 26 . Particularly interesting was the behavior of the p2 feature, which was decreasing in intensity with Co doping even though the content of Mn 4+ was increasing.…”

Magnetic order and magnetoelectric properties of R2CoMnO6 perovskites ( R=Ho , Tm, Yb, and Lu)

“…This result agrees with the findings using x-ray absorption near edge structure (XANES) spectroscopy in related double perovskites. 21,26 b. Magnetic ordering in Ho 2 CoMnO 6 and Tm 2 CoMnO 6 .…”

Resonant x-ray scattering study of charge superstructures in layeredLa2−xCaxCoOGarcı́a1, Subı́as2, Blasco3 et al. 2018Phys. Rev. BSelf Cite6250View full textAdd to dashboardCite

“…Here, the energy position of the absorption edge (E 0 ) is taken at the maximum of the derivative of the normalized f signal. Co 3+ in an octahedral oxygen environment [42] is about 2.6 eV, this means that the charge segregation between Co1 and Co2 sites is about 0.6 ± 0.1 electron. The unpolarized XANES spectra of Co1 and Co2 sites compare quite well with those of La 2 CoO 4.2 and LaSrCoO 3.99 , respectively in what regards the energy position of the absorption edge, which results in a charge difference between the nominal average Co oxidation states of 0.42 ± 0.1 electron, as reported in the Experimental section.…”