Orbital excitations in CMR progenitor of LaMnO3 studied by resonant inelastic x-ray scattering

The standard way to find the orbital occupation of Jahn-Teller (JT) ions is to use structural data, with the assumption of a one-to-one correspondence between the orbital occupation and the associated JT distortion, e.g. in O6 octahedron. We show, however, that this approach in principle does not work for layered systems. Specifically, using the layered manganite La0.5Sr1.5MnO4 as an example, we found from our x-ray absorption measurements and theoretical calculations, that t...

We present the results of a systematic x-ray scattering study of the charge and orbital ordering in the manganite series Pr$_{1-x}$Ca$_x$MnO$_3$ with $x$=0.25, 0.4 and 0.5. The temperature dependence of the scattering at the charge and orbital wavevectors, and of the lattice constants, was characterized throughout the ordered phase of each sample. It was found that the charge and orbital order wavevectors are commensurate with the lattice, in striking contrast to the results ...

Resonant soft x-ray diffraction has been used to probe the temperature dependent orbital and magnetic structure of $\mathrm{LaSr_{2}Mn_{2}O_7}$. Previous crystallographic studies have shown that this material has almost no MnO$_{6}$ oxygen displacement due to Jahn-Teller distortions at low temperatures. Within the low-temperature A-type antiferromagnetic phase, we found strong intensity at the $({1/4},{1/4},0)$ orbital and $LaSr_{2}Mn_{2}O_7$ magnetic reflections. This shows ...

The magnetic correlations in the charge- and orbital-ordered manganite La(0.5)Sr(1.5)MnO(4) have been studied by elastic and inelastic neutron scattering techniques. Out of the well-defined CE-type magnetic structure with the corresponding magnons a competition between CE-type and ferromagnetic fluctuations develops. Whereas ferromagnetic correlations are fully suppressed by the static CE-type order at low temperature, elastic and inelastic CE-type correlations disappear with...

We have utilized the resonant x-ray diffraction technique at the Mn L-edge in order to directly compare magnetic and orbital correlations in the Mn sub-lattice of Pr0.6Ca0.4MnO3. The resonant line shape is measured below T_OO ~ 240 K at the orbital ordering wave vector (0,1/2,0), and below T_N ~ 175 K at the antiferromagnetic wave vector (1/2,0,0). Comparing the width of the super-lattice peaks at the two wavevectors, we find that the correlation length of the magnetism excee...

Soft X-ray resonant scattering studies at the Mn $L_{\texttt{II, III}}$- and the La $M_{\texttt{IV, V}}$- edges of single-crystal LaSr$_2$Mn$_2$O$_7$ are reported. At low temperatures, below $T_\texttt{N} \approx 160$ K, energy scans with a fixed momentum transfer at the \emph{A}-type antiferromagnetic (0 0 1) reflection around the Mn $L_{\texttt{II, III}}$-edges with incident linear $\sigma$ and $\pi$ polarizations show strong resonant enhancements. The splitting of the ener...

We calculated the polarization-dependent Raman scattering cross section spectra of LaMnO3 below the A-type magnetic ordering temperature. Two strong peaks appear around the MnO6 octahedra stretching phonon frequency. One mode shows Ag symmetry, while the other mode shows Bg symmetry. We found that the Ag symmetry peak is a Jahn-Teller phonon coupled to the orbital wave and the Bg symmetry peak is an orbital wave coupled to a Q2 phonon mode via the Jahn-Teller electron phonon ...

Although orbital degrees of freedom are a factor of fundamental importance in strongly correlated transition metal compounds, orbital correlations and dynamics remain very difficult to access, in particular by neutron scattering. Via a direct calculation of scattering amplitudes we show that instead magnetic resonant inelastic x-ray scattering (RIXS) does reveal orbital correlations. In contrast to neutron scattering, the intensity of the magnetic excitations in RIXS depends ...

We report a synchrotron x-ray scattering study of the magnetoresistive manganite La_0.875Sr_0.125MnO_3. At low temperatures, this material undergoes an x-ray induced structural transition at which charge ordering of Mn^3+ and Mn^4+ ions characteristic to the low-temperature state of this compound is destroyed. The transition is persistent but the charge-ordered state can be restored by heating above the charge-ordering transition temperature and subsequently cooling. The char...

We present a temperature and doping dependent resonant inelastic X-ray scattering experiment at the V L$_{2,3}$ and O K edges in La$_{1-x}$Sr$_x$VO$_3$ for $x=0$ and $x=0.1$. This material is a canonical example of a compound that exhibits a filling control metal-insulator transition and undergoes orbital ordering and antiferromagnetic transitions at low temperature. Temperature dependent measurements at the V L$_{3}$ edge reveal an intra-t$_{2g}$ excitation that blueshifts b...