Abstract
The Mott-insulating rare-earth titanates (RTiO3, with R being a rare-earth ion) are an important class of materials that encompasses interesting spin-orbital phases as well as ferromagnet-antiferromagnet and insulator-metal transitions. The growth of these materials has been plagued by difficulties related to overoxidation, which arises from a strong tendency of Ti3+ to oxidize to Ti4+. We describe our efforts to grow sizable single crystals of YTiO3, Y1−xLaxTiO3 (x≤0.25), and Y1−yCayTiO3 (y≤0.35) with the optical traveling-solvent floating-zone technique. We present sample characterization via chemical composition analysis, magnetometry, charge transport, neutron scattering, x-ray absorption spectroscopy, and x-ray magnetic circular dichroism to understand macroscopic physical property variations associated with overoxidation. Furthermore, we demonstrate a good signal-to-noise ratio in inelastic magnetic neutron scattering measurements of spin-wave excitations. A superconducting impurity phase, found to appear in Ca-doped samples at high doping levels, is identified as TiO.
