Abstract
High-entropy aluminum garnets were grown as bulk single crystals using the micro-pulling-down method, taking the synthesis of complex ceramics a step further from the conventional preparation of polycrystalline materials. We studied the effects of growth parameters on the elemental distribution in high optical quality crystals of (Lu1/6Y1/6Ho1/6Dy1/6Tb1/6Gd1/6)3Al5O12 containing six cations (yttrium and rare-earths) taken in equimolar amounts. A single garnet structure was confirmed by powder X-ray diffraction. Electron microprobe measurements were obtained to correlate the radial distribution of rare-earth elements with pulling rates and molten zone height. The nature of the elemental distribution in the radial direction was associated with ionic radius: smaller rare-earths concentrated in the center of the crystal, while larger rare-earths segregated toward the outer edge of the cylindrical crystal. Faster pulling rates led to a flattening of the concentration profiles toward the nominal concentration, promoting a more homogeneous radial elemental distribution, while varying the molten zone height did not have a significant effect. The demonstrated success with crystal growth enables the practical availability of single crystals of multicomponent aluminum garnets for further discovery of new phenomena and applications.
Original language | English |
---|---|
Pages (from-to) | 6769-6776 |
Number of pages | 8 |
Journal | Crystal Growth and Design |
Volume | 20 |
Issue number | 10 |
DOIs | |
State | Published - Oct 7 2020 |
Funding
This project was supported by the National Science Foundation (DMR 1846935). One of the authors is grateful for the support from the Center for Materials Processing, University of Tennessee. Electron microprobe measurements were performed at the Electron Microprobe Laboratory in the Department of Earth and Planetary Sciences at the University of Tennessee, Knoxville, with the assistance of M. McCanta and A. Patchen. X-ray diffraction experiments were performed at the Joint Institute for Advanced Materials Diffraction Facility located at the University of Tennessee, Knoxville. A portion of this research used resources at the Spallation Neutron Source, a Department of Energy Office of Science User Facility operated by the Oak Ridge National Laboratory.