showing 4 related works from this author
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…
PtTe2: Potential new material for the growth of defect-free TeO2 single crystals
2008
Abstract The dissociation of Te–O bonds is the main drawback, which hampers the yield of large-sized paratellurite single crystals of high optical quality when using platinum crucibles. In this work, it is assumed that a catalytic dissociation process involves the intermediate formation of platinum tellurides, these ones being then responsible for entrapment of gas bubbles and black precipitates when growth proceeds. To alleviate this difficulty, we suggest that platinum ditelluride could be a chemically more appropriate compound instead of pure platinum. First experiments on direct transformation of platinum sheets into PtTe 2 under tellurium gas atmosphere are described, as well as the pr…
Bridgman growth of paratellurite single crystals
2004
Abstract The growth of paratellurite single crystals by the vertical-gradient freezing technique is reported for the first time. Boules of 120 mm long and 25 mm in diameter were obtained under a temperature gradient of 10°C cm −1 and translation rates lower than 0.6 mm h −1 . The spatial distribution of defects along the growth axis reveals a continuous evolution of the free convective fluid-flow regime as growth proceeds. Gas bubbles and dark inclusions rejected to the periphery in the upper part of the crystal are observed to lay preferentially in (1 0 0), (0 0 1), ( 1 1 ¯ 0 ) and (1 1 2) crystallographic planes. Among them, SEM and microprobe analyses evidenced the presence of metallic p…
TeO2 liquid phase: Viscosity measurements and evaluation of the thermal conductivity from crystal growth experiments
2008
Current applications of paratellurite TeO{sub 2} in optics and nuclear physics require improving the yield and optical quality of synthesized single crystals. Modelling of the growth process is a useful tool for such purpose, however, involving the knowledge of several thermodynamic parameters of both solid and liquid phase of the compound. This work describes the determination of two main unknown ones, namely dynamic viscosity {eta} and thermal conductivity {lambda}{sub l} of the liquid phase. Measurements of {eta} are performed by means of a specifically designed apparatus; over a 40 K temperature interval above the melting point we find a mean value of 0.028 Pa.s. This data is used in co…