Orbitally ordered state in Y1-xCaxTiO3 studied by resonant X-ray scattering

predictions are consistent with the experimentally obtained orbital ordering [3]. By the substitution, the number of 3d-electron on Ti ion can be controlled form 1 to 0. The FM ordering disappears at xFM~0.15, while the insulating state is preserved up to xMI~0.4. At the xMI the drastic MIT occurs and the paramagnetic-metal phase is stabilized above xMI. However, the origin of the respective phase transition is still unclear. The orbital degree of freedom in the transitions may play an important role. To make clear the orbital state in the respective phases, we have systematically investigated the orbitally ordered state in Y1-xCaxTiO3 using the resonant X-ray scattering (RXS) technique. Experiment The high quality single crystals of Y1-xCaxTiO3 were grown by a floating-zone technique. The powder x-ray diffraction at room temperature was performed to check the sample quality and the crystal structure at beam line(BL) 1B at Photon Factory. The RXS experiments were carried out by a four-circle diffractometer at BL16A2. Polarizer with a PG(004) analyzer crystal was used in some experiments. The incident x-ray energy is about 4.97 keV of Ti K-edge and the energy resolution is about 1 eV. Results