Direct observation of ordered orbital of YTiO3 by the X-ray magnetic diffraction technique

X-ray magnetic diffraction (XMD) technique was applied to an orbital ordering compound of ferromagnetic YTiO3 for the first time. The orbital-magnetic form factor μL(k) and the spin-magnetic form factor μS(k) were independently measured by utilizing the LS separation ability of the XMD. The μL(k) was measured for ten reciprocal-lattice points. No significant values of the μL(k) were observed for most of the reciprocal-lattice points within the estimated statistical errors, which suggested quenching of the orbital moment. The μS(k) was measured for 22 reciprocal-lattice points. Fourier synthesis of the μS(k) gave the spin density distribution mS(r) in the real space. The obtained mS(r) map shows the characteristic feature of the electron distribution of 3d electron in the t2g state of a Ti atom coordinated by O2− ions, in which the electrons are distributed away from the negative O2− ions. It is concluded that the electron distribution of the 3d electron of the Ti atom, that is, the ordered orbital (or the wave function) of YTiO3 was observed in the real space by the XMD technique.