High-pressure and high-temperature studies on oxide garnets

Journal Article · Sun Sep 01 00:00:00 EDT 1996 · Physical Review, B: Condensed Matter

DOI:https://doi.org/10.1103/PhysRevB.54.6200· OSTI ID:383243

Hua, H; Mirov, S; Vohra, Y K ^[1]

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1. Department of Physics, University of Alabama at Birmingham (UAB), Birmingham, Alabama 35294-1170 (United States)

We report high-pressure and high-temperature studies on a series of oxide garnets of chemical composition {ital A}{sub 3}{ital B}{sub 2}{ital C}{sub 3}O{sub 12}. The members of this family investigated are gadolinium scandium gallium garnet (GSGG), gadolinium gallium garnet (GGG), and yttrium aluminum garnet (YAG). The GSGG and GGG are doped with both neodymium and chromium while the YAG is doped only with neodymium. Photoluminescence, synchrotron x-ray-diffraction, and laser heating studies were carried out in a diamond-anvil cell. Variety of optical sensors (ruby, Sm-doped YAG) and x-ray pressure marker (copper) were employed for pressure measurement. Pressure-induced amorphization was observed in GSGG at 58{plus_minus}3 GPa and GGG at 84{plus_minus}4 GPa by x-ray-diffraction studies. The photoluminescence studies show only gradual broadening of emission bands through the amorphization transition. On increasing pressure beyond amorphization, very broad and featureless emission bands were observed in the fluorescence spectra at 77{plus_minus}2 GPa for GSGG and at 88{plus_minus}2 GPa for GGG. Laser heating of the pressure-induced amorphous phase in GSGG caused recrystallization to the stable cubic phase. High-pressure x-ray study on YAG shows that it retains cubic phase up to 101{plus_minus}4 GPa. A pressure-volume relation for each member of the oxide garnet at ambient temperatures is presented, structural transformation mechanisms, and application of oxide garnets as pressure sensors are also discussed. {copyright} {ital 1996 The American Physical Society.}

• OSTI ID: 383243
• Journal Information: Physical Review, B: Condensed Matter, Vol. 54, Issue 9; Other Information: PBD: Sep 1996
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
GADOLINIUM OXIDES
PHYSICAL PROPERTIES
SCANDIUM OXIDES
YTTRIUM OXIDES
GALLIUM OXIDES
ALUMINIUM OXIDES
CHROMIUM ADDITIONS
NEODYMIUM ADDITIONS
PHOTOLUMINESCENCE
X-RAY DIFFRACTION
LASER-RADIATION HEATING
PHASE TRANSFORMATIONS
CRYSTAL STRUCTURE
PRESSURE DEPENDENCE
VERY HIGH PRESSURE
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE 1000-4000 K