Abstract
Rare-earth titanates form very fragile liquids that can be made into glasses with useful optical properties. We investigate the atomic structure of 83TiO2-17Nd2O3 glass using pair distribution function (PDF) analysis of X-ray and neutron diffraction with double isotope substitutions for both Ti and Nd. Six total structure factors are analyzed (5 neutron + 1 X-ray) to obtain complementary sensitivities to O and Ti/Nd scattering, and an empirical potential structure refinement (EPSR) provides a structural model consistent with the experimental measurements. Glass density is estimated as 4.72(13) g cm−3, consistent with direct measurements. The EPSR model indicates nearest neighbor interactions for Ti-O at r¯ TiO = 1.984(11) Å with coordination of nTiO = 5.72(6) and for Nd-O at r¯ NdO = 2.598(22) Å with coordination of nNdO = 7.70(26), in reasonable agreement with neutron first order difference functions for Ti and Nd. The titanate glass network comprises a mixture of distorted Ti-O5 and Ti-O6 polyhedra connected via 71% corner-sharing and 23% edge-sharing. The O-Ti coordination environments include 15% nonbridging O-Ti1, 51% bridging O-Ti2, and 32% tricluster O-Ti3. This structure is highly unusual for oxide glasses melt-quenched at ambient pressure, as it consists of Ti-Ox predominantly in octahedral (with nearly no tetrahedral) coordination.
| Original language | English |
|---|---|
| Article number | 8258 |
| Journal | Scientific Reports |
| Volume | 12 |
| Issue number | 1 |
| DOIs | |
| State | Published - Dec 2022 |
| Externally published | Yes |
Funding
This work was supported by the U.S. Department of Energy (DOE) through grant DE-SC0018601 and by the National Aeronautics and Space Administration (NASA) through grant 80NSSC19K1288. HEXRD measurements were made at Sector 6-ID-D of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility, operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. ND measurements were made at the NOMAD beamline of the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. EDS measurements were made at the EPIC Facility of Northwestern University’s NUANCE Center, which has received support from the SHyNE Resource (NSF ECCS-2025633), the IIN, and Northwestern's MRSEC program (NSF DMR-1720139). Pycnometer measurements were made at the ISIS Neutron and Muon Source, run by the Science and Technology Facilities Council, UK. The authors gratefully acknowledge Dr. Sébastien Le Roux for his assistance with the R.I.N.G.S. code. This work was supported by the U.S. Department of Energy (DOE) through grant DE-SC0018601 and by the National Aeronautics and Space Administration (NASA) through grant 80NSSC19K1288. HEXRD measurements were made at Sector 6-ID-D of the Advanced Photon Source, a U.S. Department of Energy (DOE) Office of Science User Facility, operated for the DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC02-06CH11357. ND measurements were made at the NOMAD beamline of the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. EDS measurements were made at the EPIC Facility of Northwestern University’s NUANCE Center, which has received support from the SHyNE Resource (NSF ECCS-2025633), the IIN, and Northwestern's MRSEC program (NSF DMR-1720139). Pycnometer measurements were made at the ISIS Neutron and Muon Source, run by the Science and Technology Facilities Council, UK. The authors gratefully acknowledge Dr. Sébastien Le Roux for his assistance with the R.I.N.G.S. code.