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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on BaTiO3 by Materials Project

BaTiO3 crystallizes in the orthorhombic Amm2 space group. The structure is two-dimensional and consists of two BaTiO3 sheets oriented in the (0, 1, 0) direction. Ba2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are two shorter (2.56 Å) and four longer (3.07 Å) Ba–O bond lengths. Ti4+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.75 Å) and one longer (1.82 Å) Ti–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Ba2+ and one Ti4+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Ba2+ and one Ti4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2023

7.86 kV GaN-on-GaN PN power diode with BaTiO3 for electrical field management

Devices based on gallium nitride (GaN) have great potential for high power switching applications due to the high breakdown field and high electron mobility. In this work, we present a vertical GaN-on-GaN PN power diode using high dielectric constant material, BaTiO3, for electrical field management and high breakdown voltages, in together with an optimized guard-ring and field plate design. Numerical simulation shows that with high-k dielectrics implemented, the peak electrical field at the PN interface is mitigated from 3.5 to 3.1 MV/cm under a reverse bias of −9.05 kV. The device design with BaTiO3 shows a breakdown voltage of 9.65 kV or about 600 V improvement. The fabricated diodes with a 57 μm thick drift layer demonstrate a breakdown voltage of 7.86 kV on a bulk GaN substrate. The device has an on-resistance of 2.8 mΩ cm2 and a Baliga figure of merit of 22 GW/cm2.

Physics↗
DOE OSTI2020

Materials Data on BaTiO3 by Materials Project

BaTiO3 crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Ba2+ is bonded in a linear geometry to two equivalent O2- atoms. Both Ba–O bond lengths are 2.52 Å. Ti4+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Ti–O bond lengths are 2.06 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to two equivalent Ti4+ and two equivalent O2- atoms. Both O–O bond lengths are 2.06 Å. In the second O2- site, O2- is bonded to two equivalent Ba2+ and four equivalent O2- atoms to form distorted corner-sharing OBa2O4 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaTiO3 by Materials Project

BaTiO3 is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Ba2+ is bonded to twelve equivalent O2- atoms to form BaO12 cuboctahedra that share corners with twelve equivalent BaO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, and faces with eight equivalent TiO6 octahedra. All Ba–O bond lengths are 2.85 Å. Ti4+ is bonded to six equivalent O2- atoms to form TiO6 octahedra that share corners with six equivalent TiO6 octahedra and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Ti–O bond lengths are 2.02 Å. O2- is bonded in a distorted linear geometry to four equivalent Ba2+ and two equivalent Ti4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaTiO3 by Materials Project

BaTiO3 is (Cubic) Perovskite structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. Ba2+ is bonded to twelve equivalent O2- atoms to form BaO12 cuboctahedra that share corners with twelve equivalent BaO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, and faces with eight equivalent TiO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.79–3.00 Å. Ti4+ is bonded to six equivalent O2- atoms to form TiO6 octahedra that share corners with six equivalent TiO6 octahedra and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 10°. There are three shorter (1.87 Å) and three longer (2.22 Å) Ti–O bond lengths. O2- is bonded in a 2-coordinate geometry to four equivalent Ba2+ and two equivalent Ti4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaTiO3 by Materials Project

BaTiO3 is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional and consists of one titanium molecule and one BaO3 framework. In the BaO3 framework, Ba2+ is bonded to six equivalent O2- atoms to form corner-sharing BaO6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Ba–O bond lengths are 2.32 Å. O2- is bonded in a linear geometry to two equivalent Ba2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaTiO3 by Materials Project

BaTiO3 crystallizes in the orthorhombic C222_1 space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent TiO6 octahedra, faces with seven BaO12 cuboctahedra, and faces with seven TiO6 octahedra. The corner-sharing octahedra tilt angles range from 7–9°. There are a spread of Ba–O bond distances ranging from 2.83–3.08 Å. In the second Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with twelve BaO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, and faces with eight TiO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.88–2.93 Å. There are two inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent TiO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one TiO6 octahedra. The corner-sharing octahedra tilt angles range from 5–10°. There are a spread of Ti–O bond distances ranging from 1.86–2.17 Å. In the second Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six equivalent TiO6 octahedra and faces with eight BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 5–10°. There are a spread of Ti–O bond distances ranging from 1.88–2.17 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted L-shaped geometry to four Ba2+ and two equivalent Ti4+ atoms. In the second O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two Ti4+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+ and two Ti4+ atoms. In the fourth O2- site, O2- is bonded in a 6-coordinate geometry to four Ba2+ and two equivalent Ti4+ atoms. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to four Ba2+ and two Ti4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaTiO3 by Materials Project

BaTiO3 is (Cubic) Perovskite structured and crystallizes in the monoclinic Cm space group. The structure is three-dimensional. Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with twelve equivalent BaO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, and faces with eight equivalent TiO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.81–3.00 Å. Ti4+ is bonded to six O2- atoms to form distorted TiO6 octahedra that share corners with six equivalent TiO6 octahedra and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 3–11°. There are a spread of Ti–O bond distances ranging from 1.83–2.38 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to four equivalent Ba2+ and two equivalent Ti4+ atoms. In the second O2- site, O2- is bonded in a 1-coordinate geometry to four equivalent Ba2+ and two equivalent Ti4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaTiO3 by Materials Project

BaTiO3 is (Cubic) Perovskite structured and crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with twelve equivalent BaO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, and faces with eight equivalent TiO6 octahedra. There are a spread of Ba–O bond distances ranging from 2.79–3.06 Å. Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with six equivalent TiO6 octahedra and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedra tilt angles range from 8–13°. There are a spread of Ti–O bond distances ranging from 1.85–2.28 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to four equivalent Ba2+ and two equivalent Ti4+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to four equivalent Ba2+ and two equivalent Ti4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaTiO3 by Materials Project

BaTiO3 is (Cubic) Perovskite-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with nine BaO12 cuboctahedra, corners with three equivalent TiO6 octahedra, faces with seven BaO12 cuboctahedra, and faces with seven TiO6 octahedra. The corner-sharing octahedral tilt angles are 7°. There are a spread of Ba–O bond distances ranging from 2.85–3.01 Å. In the second Ba2+ site, Ba2+ is bonded to twelve O2- atoms to form BaO12 cuboctahedra that share corners with twelve BaO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, and faces with eight TiO6 octahedra. There are six shorter (2.90 Å) and six longer (2.91 Å) Ba–O bond lengths. There are two inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six O2- atoms to form TiO6 octahedra that share corners with three equivalent BaO12 cuboctahedra, corners with three equivalent TiO6 octahedra, faces with seven BaO12 cuboctahedra, and a faceface with one TiO6 octahedra. The corner-sharing octahedral tilt angles are 3°. There is three shorter (1.98 Å) and three longer (2.01 Å) Ti–O bond length. In the second Ti4+ site, Ti4+ is bonded to six equivalent O2- atoms to form TiO6 octahedra that share corners with six equivalent TiO6 octahedra and faces with eight BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 3°. All Ti–O bond lengths are 2.01 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to four Ba2+ and two Ti4+ atoms. In the second O2- site, O2- is bonded in a distorted L-shaped geometry to four Ba2+ and two equivalent Ti4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaTiO3 by Materials Project

BaTiO3 crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Ba2+ is bonded in a linear geometry to two equivalent O2- atoms. Both Ba–O bond lengths are 2.52 Å. Ti4+ is bonded in a rectangular see-saw-like geometry to four equivalent O2- atoms. There are two shorter (1.97 Å) and two longer (2.15 Å) Ti–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to two equivalent Ba2+ and four equivalent O2- atoms to form distorted corner-sharing OBa2O4 octahedra. The corner-sharing octahedra tilt angles range from 1–3°. There are two shorter (2.05 Å) and two longer (2.07 Å) O–O bond lengths. In the second O2- site, O2- is bonded in a distorted linear geometry to two equivalent Ti4+ and two equivalent O2- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Highly tunable magnetocrystalline anisotropy energy in Fe3+-doped BaTiO3

Magnetic dopants in ferroelectric oxide host materials provide a platform for electric field control of isolated spins, facilitated by tuning of the magnetocrystalline anisotropy energy (MCAE). We present first-principles calculations of the MCAE experienced by isolated Fe3+ dopants in the tetragonal, orthorhombic, and rhombohedral phases of the prototypical ferroelectric BaTiO3. We identify an order-of-magnitude decrease in the MCAE in the rhombohedral phase relative to the tetragonal and orthorhombic phases. We explain this dramatic decrease, as well as the formation of a spin-easy plane in the tetragonal phase and spin-easy axes in the orthorhombic and rhombohedral phases, using crystal field theory arguments. Building a superposition model from crystal field theory, we show how a set of simple criteria based on crystalline environment can be used to estimate the MCAE. We suggest this as a route to rapidly screen candidate ferroelectric hosts and magnetic dopants that possess phases with spin-easy axes and maximal MCAE tunability.

Barker, Bradford A↗
DOE OSTI2022

Single-Step Fabrication of Au-Fe-BaTiO3 Nanocomposite Thin Films Embedded with Non-Equilibrium Au-Fe Alloyed Nanostructures

Nanocomposite thin film materials present great opportunities in coupling materials and functionalities in unique nanostructures including nanoparticles-in-matrix, vertically aligned nanocomposites (VANs), and nanolayers. Interestingly the nanocomposites processed through a non-equilibrium processing method, e.g., pulsed laser deposition (PLD), often possess unique metastable phases and microstructures that could not achieve using equilibrium techniques, and thus lead to novel physical properties. In this work, a unique three-phase system composed of BaTiO3 (BTO), with two immiscible metals, Au and Fe, is demonstrated. By adjusting the deposition laser frequency from 2 Hz to 10 Hz, the phase and morphology of Au and Fe nanoparticles in BTO matrix vary from separated Au and Fe nanoparticles to well-mixed Au-Fe alloy pillars. This is attributed to the non-equilibrium process of PLD and the limited diffusion under high laser frequency (e.g., 10 Hz). The magnetic and optical properties are effectively tuned based on the morphology variation. This work demonstrates the stabilization of non-equilibrium alloy structures in the VAN form and allows for the exploration of new non-equilibrium materials systems and their properties that could not be easily achieved through traditional equilibrium methods.

36 MATERIALS SCIENCE↗