Investigation of local symmetry effects on the electronic structure of manganites: HexagonalYMnO3versus orthorhombicLaMnO3

Strong orbital polarization in orthorhombicDyMnO3: A combined x-ray linear dichroism andab initioelectronic structure study

“…It is clear that our spectra exhibit a very strong polarization dependence along the three different crystallographic directions in sharp contrast to the results of previous experiments on DyMnO 3 thin films which showed practically only isotropiclike spectra ͑possibly due to strain effect on substrates͒. 21,22 In our spectra, for example, the main peak for the E ʈ b polarization ͑i.e., the direction of spiral spin͒ lies at a lower energy than for polarizations E ʈ a and E ʈ c. Our spectra therefore, provide a clear indication for a large anisotropic orbital occupation of Mn e g states as expected for the strongly distorted MnO 6 octahedron. 31 To extract information on the orbital occupation from the polarization-dependent Mn L 2,3 -edge XAS spectra of DyMnO 3 , we have simulated the experimental spectra using the well-proven cluster model.…”

“…Yet, it is quite puzzling that such polarization dependence was not observed in the study on orthorhombic DyMnO 3 . 21,22 We note that thin films were used in that study. Our objective is now to resolve this issue and to reinvestigated the orbital occupations of the Mn 3d states in orthorhombic DyMnO 3 using bulk single crystals.…”

On the structural origin of the single-ion magnetic anisotropy in LuFeO3

“…Therefore, using the O K edge absorption spectra, one can infer the properties of the states that include metal (Fe and Lu) atomic contributions through hybridization. [24,26] In the case of LuFeO3, the conduction (unoccupied) states include Fe 3d, Fe 4s, Lu 6s and Lu 5d. Among these states, Fe 3d and Lu 5d are expected to be more localized and the energy distributions are narrow enough to be resolved in the x-ray absorption spectra.…”

Experimental and ab initio investigations of the x-ray absorption near edge structure of orthorhombic LuMnO3

“…22 Although having the same edge positions, orthorhombic and hexagonal LuMnO 3 show very different XANES spectra, especially in the pre-edge regions due to their different manganese coordination geometries of MnO 6 octahedra and MnO 5 trigonal bipyramids, 23 as well as the corresponding crystal field splitting and orbital hybridizations. 24 A superposition of the PFY Mn K-edge spectra of both bulk o-TMO and o-LMO samples is shown in Fig. 2(b).…”