Search results for "Sesquioxide"
showing 5 items of 5 documents
Flux growth at 1230 °C of cubic Tb2O3 single crystals and characterization of their optical and magnetic properties
2015
International audience; In this work, we present the first crystal growth of cubic Tb2O3 single crystals by a controlled atmosphere flux method which uses a heavy metal free solvent working at less than half the melting temperature of this sesquioxide. Cubic millimeter-sized crystals extracted from as-grown boules are phase (powder XRD) and chemically (GDMS) pure and exhibit a Verdet constant in the visible and near-infrared spectral ranges, which is at least three times higher than that of a commercial Tb3Ga5O12 (TGG) crystal. The 1.36 mm thick crystals display a transmission coefficient higher than 77% over the 525 nm–1.38 μm spectral range. The absorption spectrum, magnetic susceptibilit…
Synthesis of yttrium aluminum garnet nanoparticles in confined environment III: Cerium doping effect
2018
Abstract Cerium yttrium aluminum garnet (Ce:YAG, CexY3-xAl5O12) nanoparticles doped with different cerium amount were obtained by calcining the precursors synthesized via co-precipitation in w/o microemulsion for 1 h at 900 °C. The structural and morphological properties were investigated by using X-ray Diffraction (XRD), Infrared Spectroscopy (IR) and Transmission Electron Microscopy (TEM) coupled with Energy Dispersive X-ray Spectroscopy (EDS) in order to investigate the effect of doping level on formation and microstructure of obtained nanoparticles. It was found that the composition of the final products strongly depends on the concentration of cerium. The formation of single YAG phase …
Pressure effects on the vibrational properties of alpha-Bi2O3: an experimental and theoretical study
2014
We report an experimental and theoretical high-pressure study of the vibrational properties of synthetic monoclinic bismuth oxide (alpha-Bi2O3), also known as mineral bismite. The comparison of Raman scattering measurements and theoretical lattice-dynamics ab initio calculations is key to understanding the complex vibrational properties of bismite. On one hand, calculations help in the symmetry assignment of phonons and to discover the phonon interactions taking place in this low-symmetry compound, which shows considerable phonon anticrossings; and, on the other hand, measurements help to validate the accuracy of first-principles calculations relating to this compound. We have also studied …
Challenge of magnetism in strongly correlated open-shell 2p systems.
2009
We report on theoretical investigations of the exotic magnetism in rubidium sesquioxide ${\mathrm{Rb}}_{4}{\mathrm{O}}_{6}$, a model correlated system with an open $2p$ shell. Experimental investigations indicated that ${\mathrm{Rb}}_{4}{\mathrm{O}}_{6}$ is a magnetically frustrated insulator. The frustration is explained here by electronic structure calculations that incorporate the correlation between the oxygen $2p$ electrons and deal with the mixed-valent oxygen. This leads to a physical picture where the symmetry is reduced because one third of the oxygen in ${\mathrm{Rb}}_{4}{\mathrm{O}}_{6}$ is nonmagnetic while the remaining two thirds assemble in antiferromagnetic arrangements. A d…
ZnO – Yb2O3 composite optical ceramics: Synthesis, structure and spectral-luminescent properties
2022
International audience; Zinc oxide optical ceramics containing 0 – 2 wt% ytterbium are prepared byuniaxial hot pressing of commercial oxides at 1150 and 1180 °C. The ceramics have themain crystalline phase of hexagonal wurtzite-type ZnO. Ytterbium ions do not enter theZnO crystals but form a cubic sesquioxide phase of Yb2O3 located at the ZnO grainboundaries. Yb acts as an inhibitor for the ZnO grain growth. The ceramics exhibittransmittance up to 60% in the visible. Their transmission in the infrared is determinedby the free charge carrier absorption. The Yb3+ ions are found in C2 and C3i sites in Yb2O3crystals. Under X-ray excitation, the ceramics exhibit intense luminescence bands in the…