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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on YAlO3 by Materials Project

YAlO3 is Orthorhombic Perovskite structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Y3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Y–O bond distances ranging from 2.27–2.61 Å. Al3+ is bonded to six O2- atoms to form corner-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles are 28°. There are a spread of Al–O bond distances ranging from 1.92–1.94 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 5-coordinate geometry to three equivalent Y3+ and two equivalent Al3+ atoms. In the second O2- site, O2- is bonded to two equivalent Y3+ and two equivalent Al3+ atoms to form distorted corner-sharing OY2Al2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on YAlO3 by Materials Project

YAlO3 crystallizes in the trigonal R-3c space group. The structure is three-dimensional. Y3+ is bonded in a 3-coordinate geometry to nine equivalent O2- atoms. There are three shorter (2.26 Å) and six longer (2.65 Å) Y–O bond lengths. Al3+ is bonded to six equivalent O2- atoms to form corner-sharing AlO6 octahedra. The corner-sharing octahedral tilt angles are 24°. All Al–O bond lengths are 1.91 Å. O2- is bonded in a 5-coordinate geometry to three equivalent Y3+ and two equivalent Al3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on YAlO3 by Materials Project

YAlO3 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Y3+ sites. In the first Y3+ site, Y3+ is bonded in a distorted body-centered cubic geometry to eight O2- atoms. There are a spread of Y–O bond distances ranging from 2.25–2.59 Å. In the second Y3+ site, Y3+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are a spread of Y–O bond distances ranging from 2.26–2.58 Å. There are two inequivalent Al3+ sites. In the first Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. There is two shorter (1.74 Å) and two longer (1.78 Å) Al–O bond length. In the second Al3+ site, Al3+ is bonded to four O2- atoms to form corner-sharing AlO4 tetrahedra. There is two shorter (1.77 Å) and two longer (1.78 Å) Al–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Y3+ and two equivalent Al3+ atoms. In the second O2- site, O2- is bonded to three Y3+ and one Al3+ atom to form a mixture of distorted corner and edge-sharing OY3Al tetrahedra. In the third O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two equivalent Y3+ and two Al3+ atoms. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to three Y3+ and one Al3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on YAlO3 by Materials Project

YAlO3 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Y3+ is bonded to six equivalent O2- atoms to form distorted YO6 octahedra that share corners with six equivalent AlO5 trigonal bipyramids and edges with six equivalent YO6 octahedra. All Y–O bond lengths are 2.27 Å. Al3+ is bonded to five O2- atoms to form AlO5 trigonal bipyramids that share corners with six equivalent YO6 octahedra and corners with six equivalent AlO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 62°. There is two shorter (1.82 Å) and three longer (2.01 Å) Al–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a trigonal planar geometry to three equivalent Al3+ atoms. In the second O2- site, O2- is bonded to three equivalent Y3+ and one Al3+ atom to form a mixture of distorted edge and corner-sharing OY3Al tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Experimental observation of magnetic dimers in diluted Yb:YAlO 3

In this paper, we present a comprehensive experimental investigation of Yb magnetic dimers in Yb 0.04 Y 0.96 AlO 3 , an Yb-doped yttrium aluminum perovskite YAlO3, by means of specific heat, magnetization, and high-resolution inelastic neutron scattering (INS) measurements. In our sample, the Yb ions are randomly distributed over the lattice and ~7% of Yb ions form quantum dimers due to nearest-neighbor antiferromagnetic coupling along the c axis. At zero field, the dimer formation manifests itself in an appearance of an inelastic peak at Δ ≈ 0.2 meV in the INS spectrum and a Schottky-like anomaly in the specific heat. The structure factor of the INS peak exhibits a cosine modulation along the $L$ direction, in agreement with the $c$-axis nearest-neighbor intradimer coupling. A careful fitting of the low-temperature specific heat shows that the excited state is a degenerate triplet, which indicates a surprisingly small anisotropy of the effective Yb-Yb exchange interaction despite the low crystal symmetry and anisotropic magnetic dipole contribution, in agreement with previous reports for the Yb parent compound, YbAlO 3 , and in contrast to Yb 2 Pt 2 Pb. The obtained results are precisely reproduced by analytical calculations for the Yb dimers.

36 MATERIALS SCIENCE↗