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7 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on LiTaO3 by Materials Project

LiTaO3 is Ilmenite-like structured and crystallizes in the trigonal R3c space group. The structure is three-dimensional. Li1+ is bonded in a 6-coordinate geometry to six equivalent O2- atoms. There are three shorter (2.08 Å) and three longer (2.31 Å) Li–O bond lengths. Ta5+ is bonded to six equivalent O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedral tilt angles are 38°. There are three shorter (1.93 Å) and three longer (2.09 Å) Ta–O bond lengths. O2- is bonded in a distorted see-saw-like geometry to two equivalent Li1+ and two equivalent Ta5+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiTaO3 by Materials Project

LiTaO3 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. there are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are four shorter (2.43 Å) and four longer (2.72 Å) Li–O bond lengths. In the second Li1+ site, Li1+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.43 Å) and four longer (2.72 Å) Li–O bond lengths. There are two inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–30°. There is two shorter (1.97 Å) and four longer (1.99 Å) Ta–O bond length. In the second Ta5+ site, Ta5+ is bonded to six O2- atoms to form corner-sharing TaO6 octahedra. The corner-sharing octahedra tilt angles range from 0–30°. There is two shorter (1.97 Å) and four longer (1.99 Å) Ta–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to four Li1+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded to two equivalent Li1+ and two Ta5+ atoms to form a mixture of distorted edge and corner-sharing OLi2Ta2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiTaO3 by Materials Project

LiTaO3 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Li1+ is bonded to six O2- atoms to form LiO6 octahedra that share corners with six equivalent LiO6 octahedra, corners with four equivalent TaO4 tetrahedra, and edges with two equivalent TaO4 tetrahedra. The corner-sharing octahedra tilt angles range from 47–48°. There are a spread of Li–O bond distances ranging from 2.07–2.34 Å. Ta5+ is bonded to four O2- atoms to form TaO4 tetrahedra that share corners with four equivalent LiO6 octahedra, corners with two equivalent TaO4 tetrahedra, and edges with two equivalent LiO6 octahedra. The corner-sharing octahedra tilt angles range from 43–78°. There are a spread of Ta–O bond distances ranging from 1.81–1.96 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted see-saw-like geometry to two equivalent Li1+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Li1+ and one Ta5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on LiTaO3 by Materials Project

LiTaO3 is Ilmenite-like structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Li1+ is bonded to six O2- atoms to form distorted LiO6 octahedra that share corners with six equivalent LiO6 octahedra, corners with four equivalent TaO6 pentagonal pyramids, and edges with four equivalent TaO6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 54–59°. There are a spread of Li–O bond distances ranging from 1.97–2.48 Å. Ta5+ is bonded to six O2- atoms to form distorted TaO6 pentagonal pyramids that share corners with four equivalent LiO6 octahedra, corners with two equivalent TaO6 pentagonal pyramids, edges with four equivalent LiO6 octahedra, and edges with two equivalent TaO6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 52–77°. There are a spread of Ta–O bond distances ranging from 1.92–2.09 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Li1+ and two equivalent Ta5+ atoms. In the second O2- site, O2- is bonded to two equivalent Li1+ and two equivalent Ta5+ atoms to form a mixture of distorted corner and edge-sharing OLi2Ta2 trigonal pyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Latent Tracks in Ion-Irradiated LiTaO 3 Crystals: Damage Morphology Characterization and Thermal Spike Analysis

Systematic research on the response of crystal materials to the deposition of irradiation energy to electrons and atomic nuclei has attracted considerable attention since it is fundamental to understanding the behavior of various materials in natural and manmade radiation environments. This work examines and compares track formation in LiTaO3 induced by separate and combined effects of electronic excitation and nuclear collision. Under 0.71–6.17 MeV/u ion irradiation with electronic energy loss ranging from 6.0 to 13.8 keV/nm, the track damage morphologies evolve from discontinuous to continuous cylindrical zone. Based on the irradiation energy deposited via electronic energy loss, the subsequently induced energy exchange and temperature evolution processes in electron and lattice subsystems are calculated through the inelastic thermal spike model, demonstrating the formation of track damage and relevant thresholds of lattice energy and temperature. Combined with a disorder accumulation model, the damage accumulation in LiTaO3 produced by nuclear energy loss is also experimentally determined. The damage characterizations and inelastic thermal spike calculations further demonstrate that compared to damage-free LiTaO3, nuclear-collision-damaged LiTaO3 presents a more intense thermal spike response to electronic energy loss owing to the decrease in thermal conductivity and increase in electron–phonon coupling, which further enhance track damage.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Nanoscale Compositional and Strain Gradients Enable High‐Speed and Amplitude‐Resolved Pyroelectric Sensing

The frequency response of pyroelectric sensors is fundamentally governed by thermal time constant (τth, determined by thermal mass and thermal conductance) and electrical impedance arising from film capacitance and readout circuit. Conventional bulk LiTaO3 detectors are optimized for high responsivity at low modulation frequencies (0.1-10 Hz), possessing a large τth that thermally averages rapid temperature oscillations at elevated modulation frequencies, limiting fidelity in resolving dynamic varying thermal signals. Here, compositional and strain gradients are introduced into 100-nm-thick relaxor-ferroelectric films reducing τth to ≈2 µs and producing built-in potentials (≈1.45 V or 145 kV cm-1) that enhance the pyroelectric coefficient and suppress the dielectric constant. This enables complementary dual-mode operation by enhancing current-mode electrical responsivity and improving the voltage-mode figure of merit - advantageous for superior temperature resolution (ΔTmin ≈ 30 µK). The responsivity peak shifts to near 1 kHz (>2500-times higher than conventional bulk sensors), with measurable responsivity extending to a carrier frequency of 100 kHz and amplitude-resolved detection at modulation frequencies up to 15 kHz. These results establish nanoscale internal-field engineering can reshape electro-thermal trade-off in pyroelectric thin films toward zero-bias, high-thermal-sensitivity, and amplitude-resolved thermal sensing across a wide frequency bandwidth.

Lin, Ching‐Che↗
DOE OSTI2021

Ion irradiation induced strain and structural changes in LiTaO 3 perovskite

LiTaO 3 crystals irradiated with 3 MeV and 1.162 GeV Au ions were studied by single crystal x-ray diffraction and Raman scattering measurements. The maximum lattice strains after 3 MeV Au ion irradiation to a fluence of 1.2 × 10 13 cm -2 were 1.2% and 0.6% along the c- and a-/b-axes, respectively. Two effects were observed in 1.162 GeV Au ion irradiated samples: (i) the (0006) and (1120) Bragg peaks were split into doublets, which suggested a subtle structural change due to slight modification of chemical composition; and (ii) the pre-damaged 1.2% lattice strain along the c-axis was relaxed to 0.9% after subsequent irradiation with 1.162 GeV Au ions, while relaxation along the a- or b-axis was not obvious. A distinct change in the Raman spectrum of the <0001> oriented LiTaO 3 crystals was observed after 1.162 GeV Au ion irradiation, but no obvious change was observed in the <1120> oriented samples or in 3 MeV Au ion irradiated samples. Strain and structural changes in crystalline LiTaO3, with or without pre-existing defects, upon ion irradiation are delineated in its responding to inelastic ionization and elastic nuclear collisions.

36 MATERIALS SCIENCE↗