Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Gd”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 703 records · Page 39
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on GdRe2 by Materials Project

GdRe2 is Hexagonal Laves structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Gd is bonded in a 12-coordinate geometry to twelve Re atoms. There are a spread of Gd–Re bond distances ranging from 3.17–3.20 Å. There are two inequivalent Re sites. In the first Re site, Re is bonded to six equivalent Gd and six equivalent Re atoms to form a mixture of face, edge, and corner-sharing ReGd6Re6 cuboctahedra. All Re–Re bond lengths are 2.74 Å. In the second Re site, Re is bonded to six equivalent Gd and six Re atoms to form a mixture of face, edge, and corner-sharing ReGd6Re6 cuboctahedra. There are two shorter (2.66 Å) and two longer (2.80 Å) Re–Re bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GdSn2 by Materials Project

GdSn2 is Zirconium Disilicide structured and crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Gd is bonded in a 10-coordinate geometry to ten Sn atoms. There are a spread of Gd–Sn bond distances ranging from 3.19–3.48 Å. There are two inequivalent Sn sites. In the first Sn site, Sn is bonded in a 8-coordinate geometry to four equivalent Gd and four equivalent Sn atoms. All Sn–Sn bond lengths are 3.14 Å. In the second Sn site, Sn is bonded in a 4-coordinate geometry to six equivalent Gd and two equivalent Sn atoms. Both Sn–Sn bond lengths are 3.04 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GdMoBrO4 by Materials Project

GdMoO4Br crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Gd3+ sites. In the first Gd3+ site, Gd3+ is bonded in a 8-coordinate geometry to five O2- and three Br1- atoms. There are a spread of Gd–O bond distances ranging from 2.34–2.68 Å. There are one shorter (2.93 Å) and two longer (2.95 Å) Gd–Br bond lengths. In the second Gd3+ site, Gd3+ is bonded in a 6-coordinate geometry to seven O2- and one Br1- atom. There are a spread of Gd–O bond distances ranging from 2.34–2.88 Å. The Gd–Br bond length is 3.02 Å. There are two inequivalent Mo6+ sites. In the first Mo6+ site, Mo6+ is bonded in a tetrahedral geometry to four O2- atoms. There is two shorter (1.78 Å) and two longer (1.82 Å) Mo–O bond length. In the second Mo6+ site, Mo6+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of Mo–O bond distances ranging from 1.77–1.84 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Gd3+, one Mo6+, and three equivalent Br1- atoms. There are a spread of O–Br bond distances ranging from 3.40–3.62 Å. In the second O2- site, O2- is bonded in a distorted linear geometry to one Gd3+, one Mo6+, and one Br1- atom. The O–Br bond length is 3.16 Å. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two Gd3+, one Mo6+, and two equivalent Br1- atoms. There are one shorter (3.41 Å) and one longer (3.44 Å) O–Br bond lengths. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Gd3+, one Mo6+, and two equivalent Br1- atoms. There are one shorter (3.36 Å) and one longer (3.47 Å) O–Br bond lengths. In the fifth O2- site, O2- is bonded in a distorted linear geometry to one Gd3+, one Mo6+, and one Br1- atom. The O–Br bond length is 3.13 Å. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Gd3+ and one Mo6+ atom. In the seventh O2- site, O2- is bonded in a distorted linear geometry to one Gd3+ and one Mo6+ atom. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to two Gd3+ and one Mo6+ atom. There are two inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a distorted water-like geometry to two equivalent Gd3+ atoms. In the second Br1- site, Br1- is bonded in a 2-coordinate geometry to two Gd3+ and nine O2- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GdDyNi2 by Materials Project

DyGdNi2 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Dy is bonded in a 7-coordinate geometry to seven Ni atoms. There are a spread of Dy–Ni bond distances ranging from 2.87–2.94 Å. Gd is bonded in a 7-coordinate geometry to seven Ni atoms. There are a spread of Gd–Ni bond distances ranging from 2.88–2.93 Å. There are two inequivalent Ni sites. In the first Ni site, Ni is bonded in a 9-coordinate geometry to three equivalent Dy, four equivalent Gd, and two equivalent Ni atoms. Both Ni–Ni bond lengths are 2.58 Å. In the second Ni site, Ni is bonded in a 9-coordinate geometry to four equivalent Dy, three equivalent Gd, and two equivalent Ni atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Gd4Si2S3O7 by Materials Project

Gd4Si2S3O7 crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. there are two inequivalent Gd3+ sites. In the first Gd3+ site, Gd3+ is bonded in a 6-coordinate geometry to three S2- and three O2- atoms. There are two shorter (2.82 Å) and one longer (2.83 Å) Gd–S bond lengths. There are one shorter (2.34 Å) and two longer (2.47 Å) Gd–O bond lengths. In the second Gd3+ site, Gd3+ is bonded in a 9-coordinate geometry to three S2- and six O2- atoms. There are one shorter (2.89 Å) and two longer (2.91 Å) Gd–S bond lengths. There are a spread of Gd–O bond distances ranging from 2.41–2.59 Å. Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one SGd4O2 octahedra and a cornercorner with one SiO4 tetrahedra. The corner-sharing octahedral tilt angles are 64°. There is three shorter (1.64 Å) and one longer (1.65 Å) Si–O bond length. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a 4-coordinate geometry to four Gd3+ atoms. In the second S2- site, S2- is bonded to four equivalent Gd3+ and two equivalent O2- atoms to form distorted SGd4O2 octahedra that share corners with four equivalent SiO4 tetrahedra. Both S–O bond lengths are 3.17 Å. In the third S2- site, S2- is bonded in a 4-coordinate geometry to four equivalent Gd3+ and twelve O2- atoms. There are eight shorter (3.18 Å) and four longer (3.27 Å) S–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent Si4+ and one S2- atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to three Gd3+, one Si4+, and one S2- atom. In the third O2- site, O2- is bonded in a 4-coordinate geometry to three Gd3+, one Si4+, and one S2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GdBi3 by Materials Project

GdBi3 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Gd is bonded to twelve Bi atoms to form GdBi12 cuboctahedra that share corners with four equivalent GdBi12 cuboctahedra, edges with eight equivalent GdBi12 cuboctahedra, edges with sixteen equivalent BiGd4Bi8 cuboctahedra, faces with four equivalent GdBi12 cuboctahedra, and faces with eight equivalent BiGd4Bi8 cuboctahedra. There are four shorter (3.31 Å) and eight longer (3.58 Å) Gd–Bi bond lengths. There are two inequivalent Bi sites. In the first Bi site, Bi is bonded to four equivalent Gd and eight Bi atoms to form distorted BiGd4Bi8 cuboctahedra that share corners with twelve equivalent BiGd4Bi8 cuboctahedra, edges with eight equivalent GdBi12 cuboctahedra, edges with eight equivalent BiGd4Bi8 cuboctahedra, faces with four equivalent GdBi12 cuboctahedra, and faces with ten equivalent BiGd4Bi8 cuboctahedra. There are four shorter (3.31 Å) and four longer (3.58 Å) Bi–Bi bond lengths. In the second Bi site, Bi is bonded in a square co-planar geometry to four equivalent Gd and eight equivalent Bi atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Gd4B4O11F2 by Materials Project

Gd4B4O11F2 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are two inequivalent Gd3+ sites. In the first Gd3+ site, Gd3+ is bonded in a 10-coordinate geometry to nine O2- and one F1- atom. There are a spread of Gd–O bond distances ranging from 2.38–2.79 Å. The Gd–F bond length is 2.46 Å. In the second Gd3+ site, Gd3+ is bonded in a 9-coordinate geometry to six O2- and three equivalent F1- atoms. There are a spread of Gd–O bond distances ranging from 2.31–2.47 Å. There are a spread of Gd–F bond distances ranging from 2.51–2.87 Å. There are two inequivalent B3+ sites. In the first B3+ site, B3+ is bonded to four O2- atoms to form corner-sharing BO4 tetrahedra. There are a spread of B–O bond distances ranging from 1.42–1.58 Å. In the second B3+ site, B3+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of B–O bond distances ranging from 1.37–1.40 Å. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Gd3+ and two B3+ atoms. In the second O2- site, O2- is bonded in a distorted single-bond geometry to three Gd3+ and one B3+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to three Gd3+ and one B3+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Gd3+ and two equivalent B3+ atoms. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to three Gd3+ and one B3+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to three Gd3+ and one B3+ atom. F1- is bonded in a 3-coordinate geometry to four Gd3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr2GdS3 by Materials Project

Sr2GdS3 crystallizes in the orthorhombic Amm2 space group. The structure is two-dimensional and consists of one Sr2GdS3 sheet oriented in the (0, 0, 1) direction. Sr is bonded in a single-bond geometry to five S atoms. There are a spread of Sr–S bond distances ranging from 2.89–2.91 Å. Gd is bonded to six S atoms to form a mixture of edge and corner-sharing GdS6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Gd–S bond distances ranging from 2.90–2.92 Å. There are two inequivalent S sites. In the first S site, S is bonded to two equivalent Sr and four equivalent Gd atoms to form SSr2Gd4 octahedra that share corners with four equivalent SSr2Gd4 octahedra, edges with four equivalent SSr2Gd4 octahedra, and edges with eight equivalent SSr4Gd square pyramids. The corner-sharing octahedral tilt angles are 0°. In the second S site, S is bonded to four equivalent Sr and one Gd atom to form SSr4Gd square pyramids that share corners with five equivalent SSr4Gd square pyramids, edges with four equivalent SSr2Gd4 octahedra, and edges with four equivalent SSr4Gd square pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaGdS2 by Materials Project

CaGdS2 is Caswellsilverite-like structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Ca is bonded to six S atoms to form CaS6 octahedra that share corners with six equivalent CaS6 octahedra, edges with four equivalent CaS6 octahedra, and edges with eight equivalent GdS6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.81 Å) and two longer (2.82 Å) Ca–S bond lengths. Gd is bonded to six S atoms to form GdS6 octahedra that share corners with six equivalent GdS6 octahedra, edges with four equivalent GdS6 octahedra, and edges with eight equivalent CaS6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.81 Å) and two longer (2.82 Å) Gd–S bond lengths. There are two inequivalent S sites. In the first S site, S is bonded to two equivalent Ca and four equivalent Gd atoms to form a mixture of corner and edge-sharing SCa2Gd4 octahedra. The corner-sharing octahedral tilt angles are 0°. In the second S site, S is bonded to four equivalent Ca and two equivalent Gd atoms to form SCa4Gd2 octahedra that share corners with six equivalent SCa4Gd2 octahedra and edges with twelve SCa2Gd4 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GdWBrO4 by Materials Project

GdWO4Br crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Gd3+ sites. In the first Gd3+ site, Gd3+ is bonded in a 8-coordinate geometry to five O2- and three Br1- atoms. There are a spread of Gd–O bond distances ranging from 2.32–2.79 Å. There are a spread of Gd–Br bond distances ranging from 2.94–2.96 Å. In the second Gd3+ site, Gd3+ is bonded in a 6-coordinate geometry to six O2- and one Br1- atom. There are a spread of Gd–O bond distances ranging from 2.32–2.52 Å. The Gd–Br bond length is 3.03 Å. There are two inequivalent W6+ sites. In the first W6+ site, W6+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of W–O bond distances ranging from 1.80–1.84 Å. In the second W6+ site, W6+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of W–O bond distances ranging from 1.79–1.86 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Gd3+, one W6+, and three equivalent Br1- atoms. There are a spread of O–Br bond distances ranging from 3.39–3.67 Å. In the second O2- site, O2- is bonded in a distorted linear geometry to one Gd3+, one W6+, and one Br1- atom. The O–Br bond length is 3.20 Å. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two Gd3+, one W6+, and two equivalent Br1- atoms. There are one shorter (3.43 Å) and one longer (3.46 Å) O–Br bond lengths. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two Gd3+, one W6+, and two equivalent Br1- atoms. There are one shorter (3.35 Å) and one longer (3.50 Å) O–Br bond lengths. In the fifth O2- site, O2- is bonded in a distorted linear geometry to one Gd3+, one W6+, and one Br1- atom. The O–Br bond length is 3.17 Å. In the sixth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Gd3+ and one W6+ atom. In the seventh O2- site, O2- is bonded in a distorted linear geometry to one Gd3+ and one W6+ atom. In the eighth O2- site, O2- is bonded in a 3-coordinate geometry to two Gd3+ and one W6+ atom. There are two inequivalent Br1- sites. In the first Br1- site, Br1- is bonded in a distorted water-like geometry to two equivalent Gd3+ atoms. In the second Br1- site, Br1- is bonded in a 2-coordinate geometry to two Gd3+ and nine O2- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GdGa6 by Materials Project

GdGa6 crystallizes in the tetragonal P4/nbm space group. The structure is three-dimensional. Gd is bonded to twelve Ga atoms to form a mixture of face and edge-sharing GdGa12 cuboctahedra. There are four shorter (3.11 Å) and eight longer (3.26 Å) Gd–Ga bond lengths. There are two inequivalent Ga sites. In the first Ga site, Ga is bonded in a 9-coordinate geometry to four equivalent Gd and five Ga atoms. There are one shorter (2.48 Å) and four longer (2.63 Å) Ga–Ga bond lengths. In the second Ga site, Ga is bonded in a 4-coordinate geometry to one Gd and three Ga atoms. The Ga–Ga bond length is 2.52 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Dual-Responsive Turn-On T 1 Imaging-Guided Mild Photothermia for Precise Apoptotic Cancer Therapy

Apoptosis has gained increasing attention in cancer therapy as an intrinsic signaling pathway, which leads to minimal leakage of waste products from a dying cell to neighboring normal cells. Among various stimuli to trigger apoptosis, mild hyperthermia is attractive but confronts limitations of non-specific heating and acquired resistance from elevated expression of heat shock proteins. Here, a dual-stimulation activated turn-on T 1 imaging-based nanoparticulate system (DAS) is developed for mild photothermia (≈43 °C)-mediated precise apoptotic cancer therapy. In the DAS, a superparamagnetic quencher (ferroferric oxide nanoparticles, Fe 3 O 4 NPs) and a paramagnetic enhancer (Gd-DOTA complexes) are connected via the N6-methyladenine (m 6 A)-caged, Zn 2+ -dependent DNAzyme molecular device. The substrate strand of the DNAzyme contains one segment of Gd-DOTA complex-labeled sequence and another one of HSP70 antisense oligonucleotide. When the DAS is taken up by cancer cells, overexpressed fat mass and obesity-associated protein (FTO) specifically demethylates the m 6</-sup>A group, thereby activating DNAzymes to cleave the substrate strand and simultaneously releasing Gd-DOTA complex-labeled oligonucleotides. The restored T 1 signal from the liberated Gd-DOTA complexes lights up the tumor to guide the location and time of deploying 808 nm laser irradiation. Afterward, locally generated mild photothermia works in concert with HSP70 antisense oligonucleotides to promote apoptosis of tumor cells. This highly integrated design provides an alternative strategy for mild hyperthermia-mediated precise apoptotic cancer therapy.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2023

Chemical durability of multicomponent lanthanide zirconate solid solutions

Multicomponent zirconate solid solutions A 2 Zr 2 O 7 (A= (Sm,Yb), (Sm,Yb,Gd), (Sm,Yb,Gd,Er), and (Sm,Yb,Gd,Er,Dy)) were synthesized through spark plasma sintering and their chemical durability was investigated via semi-dynamic leaching tests in pH = 1 nitric acid at 90°C. Incongruent dissolution occurred for all samples with the preferential elemental release of zirconium in all A 2 Zr 2 O 7 except for high entropy (Sm,Yb,Gd,Er,Dy)Zr 2 O 7 which displays a congruent release of the A-site elements and Zr. A strong positive correlation was found between the lanthanide elemental release rates and the A-site cation size disorder, whereas a negative correlation was observed between the elemental release rates and mixing entropy.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Terahertz EPR spectroscopy using a 36-tesla high-homogeneity series-connected hybrid magnet

Electron Paramagnetic Resonance (EPR) is a powerful technique to study materials and biological samples on an atomic scale. High-field EPR in particular enables extracting very small g-anisotropies in organic radicals and half-filled 3d and 4f metal ions such as Mn II (3d 5 ) or Gd III (4f 7 ), and resolving EPR signals from unpaired spins with very close g-values, both of which provide high-resolution details of the local atomic environment. Before the recent commissioning of the high-homogeneity Series Connected Hybrid magnet (SCH, superconducting + resistive) at the National High Magnetic Field Laboratory (NHMFL), the highest-field, high-resolution EPR spectrometer available was limited to 25 T using a purely resistive “Keck” magnet at the NHMFL. Herein, we report the first EPR experiments performed using the SCH magnet capable of reaching the field of 36 T, corresponding to an EPR frequency of 1 THz for g = 2. The magnet’s intrinsic homogeneity (25 ppm, that is 0.9 mT at 36 T over 1 cm diameter, 1 cm length cylinder) was previously established by NMR. We characterized the magnet’s temporal stability (5 ppm, which is 0.2 mT at 36 T over one-minute, the typical acquisition time) using 2,2-diphenyl-1-picrylhydrazyl (DPPH). This high resolution enables resolving the weak g-anisotropy of 1,3-bis(diphenylene)-2-phenylallyl (BDPA), Δg = 2.5 × 10 –4 obtained from measurements at 932 GHz and 33 T. Subsequently, we recorded EPR spectra at multiple frequencies for two Gd III complexes with potential applications as spin labels. In conclusion, we demonstrated a significant reduction in line broadening in Gd[DTPA], attributed to second order zero field splitting, and a resolution enhancement of g-tensor anisotropy for Gd[sTPATCN]-SL.

47 OTHER INSTRUMENTATION↗
DOE OSTI2023

Accelerating gradient descent and Adam via fractional gradients

Here we propose a class of novel fractional-order optimization algorithms. We define a fractional-order gradient via the Caputo fractional derivatives that generalizes integer-order gradient. We refer it to as the Caputo fractional-based gradient, and develop an efficient implementation to compute it. A general class of fractional-order optimization methods is then obtained by replacing integer-order gradients with the Caputo fractional-based gradients. To give concrete algorithms, we consider gradient descent (GD) and Adam, and extend them to the Caputo fractional GD (CfGD) and the Caputo fractional Adam (CfAdam). We demonstrate the superiority of CfGD and CfAdam on several large scale optimization problems that arise from scientific machine learning applications, such as ill-conditioned least squares problem on real-world data and the training of neural networks involving non-convex objective functions. Numerical examples show that both CfGD and CfAdam result in acceleration over GD and Adam, respectively. We also derive error bounds of CfGD for quadratic functions, which further indicate that CfGD could mitigate the dependence on the condition number in the rate of convergence and results in significant acceleration over GD.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2021

Measurement of neutral gadolinium oscillator strengths using dual-comb absorption spectroscopy in laser-produced plasmas

The oscillator strengths of 43 transitions of neutral gadolinium from 530 to 535 nm were determined based on high-resolution absorption spectra measured by probing a laser-produced plasma (LPP) using time-resolved dual-comb spectroscopy (DCS). Absorption spectra were measured at various time delays, ranging from 33 to 252 µs after the onset of the plasma formation, over which the temperature and number density varied as the ablation plume evolved. A Boltzmann analysis was used to determine the excitation temperature and column density of Gd in the ablation plume, based on measured absorption from 20 Gd I spectral lines with known oscillator strengths. Oscillator strengths were then determined for additional dipole-allowed Gd I transitions identified in the absorption spectra, 19 of which were previously unreported. Oscillator strengths of all measured transitions were compared with literature values when available and show good agreement in most cases. Time-resolved measurement of atomic absorption in the cooling plasma provides access to a range of excitation temperatures and optical densities for the atoms in the ablation plume, allowing repeated measurements under different conditions, thereby improving confidence in the results. The high spectral bandwidth and resolution capabilities of DCS make it well-suited to measuring the dense optical spectrum of Gd, and the technique is applicable to other elements, especially lanthanides and actinides.

(280.4788) Optical Sensing, (280.5395) Plasma Diag↗
DOE OSTI2025

Influence of Compositional Complexity on Amorphization Resistance of Swift Heavy Ion Irradiated Titanate Pyrochlores

Compositionally complex oxides have garnered attention recently for their potential technological applications in harsh environments such as thermal barrier coatings and nuclear waste forms. Therefore, their response to extreme conditions, including high temperature and intense irradiation fields, must be thoroughly investigated. Here, the structural evolution of two pyrochlore oxides with comparable cation size ratio, r A /r B , (Yb 0.2 Er 0.2 Dy 0.2 Tb 0.2 Gd 0.2 ) 2 Ti 2 O 7 and Ho 2 Ti 2 O 7 , was evaluated after irradiation with 946 MeV Au ions up to a fluence of 8 × 10 12 ions/cm2 using synchrotron X-ray diffraction, transmission electron microscopy, and Raman spectroscopy. The overall radiation response is comparable for both titanate oxides and is dominated by a loss of crystallinity. When compared to a series of conventional titanate pyrochlore compositions, the amorphous track diameter of (Yb 0.2 Er 0.2 Dy 0.2 Tb 0.2 Gd 0.2 ) 2 Ti 2 O 7 is slightly larger than that of Ho2Ti2O7 and more in line with the diameter of the endmember with the maximum A-site cation size (Gd 2 Ti 2 O 7 ). Density functional theory calculations suggest that this behavior may be linked to local lattice distortions and the associated energetics of cation antisite formation. TEM and Raman analyses show that a disordered, crystalline shell surrounds the amorphous ion tracks in (Yb 0.2 Er 0.2 Dy 0.2 Tb 0.2 Gd 0.2 ) 2 Ti 2 O 7 , and the corresponding short-range structure resembles a weberite-type atomic arrangement.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗