Spin resolved electron density study of YTiO 3 in its ferromagnetic phase: signature of orbital ordering

• Published in: IUCrJ Vol. 6; no. 5; pp. 884 - 894
• Main Authors: Voufack, Ariste Bolivard, Kibalin, Iurii, Yan, Zeyin, Claiser, Nicolas, Gueddida, Saber, Gillon, Béatrice, Porcher, Florence, Gukasov, Arsen, Sugimoto, Kunishisa, Lecomte, Claude, Dahaoui, Slimane, Gillet, Jean-Michel, Souhassou, Mohamed
• Format: Journal Article
• Language: English
• Published: International Union of Crystallography 01.09.2019
• Subjects: Condensed Matter; Materials Science; Physics; perovskites; polarized neutron diffraction; orbital ordering; X-ray diffraction; multipolar refinement; magnetic order; properties of solids; materials modelling; inorganic materials; computational modelling; charge density; YTiO 3; spin density
• ISSN: 2052-2525; 2052-2525
• DOI: 10.1107/S2052252519009230

The present work reports on the charge and spin density modelling of YTiO 3 in its ferromagnetic state ( T C = 27 K). Accurate polarized neutron diffraction and high-resolution X-ray diffraction (XRD) experiments were carried out on a single crystal at the ORPHÉE reactor (LLB) and SPRING8 synchrotron source. The experimental data are modelled by the spin resolved pseudo-atomic multipolar model (Deutsch et al. , 2012). The refinement strategy is discussed and the result of this electron density modelling is compared with that from XRD measured at 100 K and with density functional theory calculations. The results show that the spin and charge densities around the Ti atom have lobes directed away from the O atoms, confirming the filling of the t 2g orbitals of the Ti atom. The d xy orbital is less populated than d xz and d yz , which is a sign of a partial lift of degeneracy of the t 2g orbitals. This study confirms the orbital ordering at low temperature (20 K), which is already present in the paramagnetic state above the ferromagnetic transition (100 K).