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DOE OSTI2020

Materials Data on Pr(GePd)2 by Materials Project

PrPd2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Pr is bonded in a 8-coordinate geometry to eight equivalent Pd and eight equivalent Ge atoms. All Pr–Pd bond lengths are 3.37 Å. All Pr–Ge bond lengths are 3.33 Å. Pd is bonded in a 4-coordinate geometry to four equivalent Pr and four equivalent Ge atoms. All Pd–Ge bond lengths are 2.55 Å. Ge is bonded in a 9-coordinate geometry to four equivalent Pr, four equivalent Pd, and one Ge atom. The Ge–Ge bond length is 2.52 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Pr(Cd10Pd)2 by Materials Project

Pr(PdCd10)2 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Pr is bonded in a 4-coordinate geometry to sixteen Cd atoms. There are four shorter (3.46 Å) and twelve longer (3.48 Å) Pr–Cd bond lengths. Pd is bonded to twelve Cd atoms to form PdCd12 cuboctahedra that share corners with six equivalent PdCd12 cuboctahedra, edges with eighteen equivalent CdPrCd10Pd cuboctahedra, and faces with six equivalent CdPrCd10Pd cuboctahedra. There are six shorter (2.83 Å) and six longer (3.14 Å) Pd–Cd bond lengths. There are three inequivalent Cd sites. In the first Cd site, Cd is bonded in a distorted linear geometry to two equivalent Pd and six equivalent Cd atoms. There are two shorter (3.00 Å) and four longer (3.17 Å) Cd–Cd bond lengths. In the second Cd site, Cd is bonded to one Pr, one Pd, and ten Cd atoms to form distorted CdPrCd10Pd cuboctahedra that share corners with fifteen equivalent CdPrCd10Pd cuboctahedra, edges with two equivalent CdPrCd10Pd cuboctahedra, edges with three equivalent PdCd12 cuboctahedra, a faceface with one PdCd12 cuboctahedra, and faces with fifteen equivalent CdPrCd10Pd cuboctahedra. There are a spread of Cd–Cd bond distances ranging from 2.92–3.39 Å. In the third Cd site, Cd is bonded in a distorted linear geometry to two equivalent Pr and twelve equivalent Cd atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Pr by Materials Project

Pr is Copper-like structured and crystallizes in the trigonal P3_121 space group. The structure is three-dimensional. Pr is bonded to twelve equivalent Pr atoms to form a mixture of corner, edge, and face-sharing PrPr12 cuboctahedra. There are a spread of Pr–Pr bond distances ranging from 3.67–3.79 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Pr by Materials Project

Pr is Protactinium structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Pr is bonded in a 10-coordinate geometry to ten equivalent Pr atoms. There are eight shorter (3.62 Å) and two longer (3.76 Å) Pr–Pr bond lengths.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Pr by Materials Project

Pr is Tungsten structured and crystallizes in the cubic Im-3m space group. The structure is three-dimensional. Pr is bonded in a distorted body-centered cubic geometry to eight equivalent Pr atoms. All Pr–Pr bond lengths are 3.62 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Pr by Materials Project

Pr is Magnesium structured and crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Pr is bonded to twelve equivalent Pr atoms to form a mixture of face, edge, and corner-sharing PrPr12 cuboctahedra. There are a spread of Pr–Pr bond distances ranging from 3.62–3.78 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Pr by Materials Project

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Pr by Materials Project

Pr is Copper structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Pr is bonded to twelve equivalent Pr atoms to form a mixture of edge, corner, and face-sharing PrPr12 cuboctahedra. There are a spread of Pr–Pr bond distances ranging from 3.63–3.80 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Pr by Materials Project

Pr is Magnesium structured and crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Pr is bonded to twelve equivalent Pr atoms to form a mixture of edge, face, and corner-sharing PrPr12 cuboctahedra. There are a spread of Pr–Pr bond distances ranging from 3.67–3.77 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2023

Interplay Between Kondo and Magnetic Interactions in Pr 0.75 Gd 0.25 ScGeH

Combined experimental and density functional theory (DFT) study of Pr 0.75 Gd 0.25 ScGe and its hydride (Pr 0.75 Gd 0.25 ScGeH) reveals intricacies of composition-structure-property relationships in those distinctly layered compounds. Hydrogenation of the intermetallic parent, crystalizing in a tetragonal CeScSi-type structure, leads to an anisotropic volume expansion, that is, a(=b) lattice parameter decreases while the lattice expands along the c direction, yielding a net increase of cell volume. DFT calculations predict an antiparallel coupling of localized Gd and Pr magnetic moments in both materials at the ground state. While experiments corroborate this for the parent compound, there is no conclusive experimental proof for the hydride, where Pr moments do not order down to 3 K. DFT results also reveal that rare-earth – hydrogen interactions reduce spin-polarization of the Pr and Gd 5d and Sc 3d states at the Fermi energy, disrupt indirect exchange interactions mediated by conduction electrons, dramatically reduce the magnetic ordering temperature, and open a pseudo-gap in the majority-spin channel. Here, both experiments and theory show evidence of Kondo-like behavior in the hydride in the absence of an applied magnetic field, whereas increasing the field promotes magnetic ordering and suppresses Kondo-like behavior.

36 MATERIALS SCIENCE↗

DOE OSTI2025

Structural, magnetic, optical, dielectric and electronic properties of R 2 NiIrO 6 (R = Pr and Nd): A comprehensive experimental and theoretical investigation

Double perovskites are highly promising materials capable of exhibiting a wide variety of phenomena. In this work, we perform a comprehensive experimental and theoretical study of polycrystalline R 2 NiIrO 6 (R = Pr and Nd) compounds. Both compounds were synthesised using the solid-state reaction method. Rietveld refinement confirmed a monoclinic structure with the P2 1 /n space group for both compounds. The scanning electron images showed the average grain sizes of 0.55 μm for R = Pr and 0.46 μm for R = Nd. Fourier transform infrared ra- diation spectra of the two compounds presented two intense bands at 470 cm -1 and 540 cm -1 . The optical measurements revealed that the band gaps of the compounds were in the visible absorption range. The field- cooled magnetisation - field hysteresis measurements indicated exchange bias properties in the synthesised compounds at low temperatures. Both temperature and frequency variation of dielectric constant and loss tangent measurements were conducted. The frequency-dependent ac conductivity measurements indicated that the conductivity increases with the increase of frequency as well as temperature. The Nd 2 NiIrO 6 compound showed lower ac conductivities compared to its isostructural Pr 2 NiIrO 6 compound. The atomic and electronic structures of Nd 2 NiIrO 6 and Pr 2 NiIrO 6 were explored using the spin-polarised calculations performed within the DFT+U method. Our results suggested that the inclusion of on-site correlations and repulsions for the d-states of atoms was necessary in order to obtain finite band gaps of Nd 2 NiIrO 6 and Pr 2 NiIrO 6 systems.

36 MATERIALS SCIENCE↗

DOE OSTI2022

Competing Charge/Spin-Stripe and Correlated Metal Phases in Trilayer Nickelates (Pr 1– x La x ) 4 Ni 3 O 8

We report low valent nickelates R n+1 Ni n O 2n+2 (R = rare earth) containing Ni 1+ (d 9 ) with a quasi-two-dimensional (quasi-2D) square-planar coordination geometry possess structural and electronic properties that are similar to those of high T c cuprates, including superconductivity itself in the doped infinite-layer (n = ∞) RNiO 2 system. Within this R n+1 Ni n O 2n+2 nickelate family, the crystallographic isomorphs Pr 4 Ni 3 O 8 and La 4 Ni 3 O 8 exhibit singularly different ground states: Pr 4 Ni 3 O 8 is metallic, and La 4 Ni 3 O 8 is a charge- and spin-stripe-ordered insulator. To explore and understand the ground state evolution from metallic Pr 4 Ni 3 O 8 to stripe-ordered La 4 Ni 3 O 8 in the R 4 Ni 3 O 8 family, we have grown a series of isovalent, substituted single crystals (Pr 1-x La x ) 4 Ni 3 O 8 . Combining thermodynamic, transport, magnetic, and synchrotron X-ray single crystal diffraction measurements, we reveal a T = 0 transition between metallic and stripe-insulator phase regions, with this putative quantum phase transition at x ≈ 0.45. We propose two possible models for (Pr 1-x La x ) 4 Ni 3 O 8 : an electronically inhomogeneous system that could serve as a candidate for exploring quantum Griffiths phase physics or a homogeneous system with a clean quantum critical point at the phase boundary

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

DOE OSTI2023

Absence of mixed valency for Pr in pristine and hole-doped PrNiO 2

Infinite-layer nickelates (𝑅⁢NiO 2 ) exhibit some distinct differences as compared to cuprate superconductors, leading to a debate concerning the role of rare-earth ions (𝑅=La,Pr,Nd) in the low-energy many-body physics. Although rare-earth 4⁢𝑓 orbitals are typically treated as inert “core” electrons in studies, this approximation has been questioned. An active participation of 4⁢𝑓 states is most likely for PrNiO 2 based on an analogy to cuprates where Pr cuprates differ significantly from other cuprates. Here, we adopt density functional plus dynamical mean-field theory to investigate the role of Pr 4⁢𝑓 orbitals and more generally the correlated electronic structure of PrNiO 2 and its hole-doped variant. We find that the Pr 4⁢𝑓 states are insulating and show no evidence for either a Kondo resonance or Zhang-Rice singlet formation as they do not have any hybridization channels near the Fermi energy. The biggest effects of hole doping are to shift the Pr 5⁢𝑑 and 4⁢𝑓 states further away from the Fermi energy whereas enhancing the Ni 3⁢𝑑−O 2⁢𝑝 hybridization, thus, reducing correlation effects as the O 2⁢𝑝 states get closer to the Fermi energy. We again find no evidence for either Kondo or Zhang-Rice physics for the 4⁢𝑓 states upon hole doping. Finally, we conclude by commenting on implications for other reduced valence nickelates.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2020

High oxygen pressure floating zone growth and crystal structure of the metallic nickelates R4Ni3O10 ( R=La,Pr )

Single crystals of the metallic Ruddlesden-Popper trilayer nickelates R 4 Ni 3 O 10 ( R = La , Pr ) were successfully grown using an optical-image floating zone furnace under oxygen pressure ( p O 2 ) of 20 bar for La 4 Ni 3 O 10 and 140 bar for Pr 4 Ni 3 O 10 . Furthermore, a combination of synchrotron and laboratory x-ray single-crystal diffraction, high-resolution synchrotron x-ray powder diffraction and measurements of physical properties revealed that R 4 Ni 3 O 10 ( R = La , Pr ) crystallizes in the monoclinic P 2 1 / a ( Z = 2 ) space group at room temperature, and that a metastable orthorhombic phase ( Bmab ) can be trapped by postgrowth rapid cooling. Both La 4 Ni 3 O 10 and Pr 4 Ni 3 O 10 crystals undergo a metal-to-metal transition (MMT) below room temperature. In the case of Pr 4 Ni 3 O 10 , the MMT is found at 157.6 K. For La 4 Ni 3 O 10 , the MMT depends on the lattice symmetry: 147.5 K for Bmab vs 138.6 K for P 2 1 / a . Lattice anomalies were found at the MMT that, when considered together with the pronounced dependence of the transition temperature on subtle structural differences between Bmab and P 2 1 / a phases, demonstrate a not insignificant coupling between electronic and lattice degrees of freedom in these trilayer nickelates.

36 MATERIALS SCIENCE↗

DOE OSTI2021

Relationship between A-site cation and magnetic structure in 3d–5d–4f double perovskite iridates Ln 2 NiIrO 6 ( Ln = La, Pr, Nd)

We report a comprehensive investigation of Ln 2 NiIrO 6 (Ln=La, Pr, Nd) using thermodynamic and transport properties, neutron powder diffraction, resonant inelastic x-ray scattering, and density-functional theory (DFT) calculations to investigate the role of A-site cations on the magnetic interactions in this family of hybrid 3d–5d–4f compositions. Magnetic structure determination using neutron diffraction reveals antiferromagnetism for La 2 NiIrO 6 , a collinear ferrimagnetic Ni and Ir state that is driven to long-range antiferromagnetism upon the onset of Nd ordering in Nd 2 NiIrO 6 , and a noncollinear ferrimagnetic Ni and Ir sublattice interpenetrated by a ferromagnetic Pr lattice for Pr 2 NiIrO 6 . For Pr 2 NiIrO 6 , heat-capacity results reveal the presence of two independent magnetic sublattices, and transport resistivity indicates insulating behavior and a conduction pathway that is thermally mediated. Here, a first principles DFT calculation elucidates the existence of the two independent magnetic sublattices within Pr 2 NiIrO 6 and offers insight into the behavior in La 2 NiIrO 6 and Nd 2 NiIrO 6 . Resonant inelastic x-ray scattering is consistent with spin-orbit coupling splitting the t 2 g manifold of octahedral Ir 4+ into a J eff = 1/2 and J eff = 3/2 state for all members of the series considered.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Pr(Al10Cr)2 by Materials Project

PrCr2Al20 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Pr is bonded in a 4-coordinate geometry to sixteen Al atoms. There are four shorter (3.14 Å) and twelve longer (3.25 Å) Pr–Al bond lengths. Cr is bonded to twelve Al atoms to form CrAl12 cuboctahedra that share corners with six equivalent CrAl12 cuboctahedra, edges with eighteen equivalent AlPrAl10Cr cuboctahedra, and faces with six equivalent AlPrAl10Cr cuboctahedra. There are six shorter (2.57 Å) and six longer (2.77 Å) Cr–Al bond lengths. There are three inequivalent Al sites. In the first Al site, Al is bonded in a 12-coordinate geometry to two equivalent Cr and ten Al atoms. There are a spread of Al–Al bond distances ranging from 2.71–2.82 Å. In the second Al site, Al is bonded in a linear geometry to two equivalent Pr and twelve equivalent Al atoms. All Al–Al bond lengths are 3.13 Å. In the third Al site, Al is bonded to one Pr, one Cr, and ten Al atoms to form distorted AlPrAl10Cr cuboctahedra that share corners with fifteen equivalent AlPrAl10Cr cuboctahedra, edges with two equivalent AlPrAl10Cr cuboctahedra, edges with three equivalent CrAl12 cuboctahedra, a faceface with one CrAl12 cuboctahedra, and faces with fifteen equivalent AlPrAl10Cr cuboctahedra. There are a spread of Al–Al bond distances ranging from 2.76–2.89 Å.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Pr(TiAl10)2 by Materials Project

Ti2Al20Pr crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. Pr is bonded in a 4-coordinate geometry to sixteen Al atoms. There are four shorter (3.19 Å) and twelve longer (3.26 Å) Pr–Al bond lengths. Ti is bonded to twelve Al atoms to form corner-sharing TiAl12 cuboctahedra. There are six shorter (2.61 Å) and six longer (2.84 Å) Ti–Al bond lengths. There are three inequivalent Al sites. In the first Al site, Al is bonded in a 12-coordinate geometry to one Pr, one Ti, and ten Al atoms. There are a spread of Al–Al bond distances ranging from 2.76–3.15 Å. In the second Al site, Al is bonded in a 12-coordinate geometry to two equivalent Ti and ten Al atoms. All Al–Al bond lengths are 2.85 Å. In the third Al site, Al is bonded in a linear geometry to two equivalent Pr and twelve equivalent Al atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on Pr(NO3)3 by Materials Project

Pr(NO3)3 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent Pr3+ sites. In the first Pr3+ site, Pr3+ is bonded to twelve O2- atoms to form corner-sharing PrO12 cuboctahedra. There are a spread of Pr–O bond distances ranging from 2.63–2.69 Å. In the second Pr3+ site, Pr3+ is bonded to twelve O2- atoms to form distorted corner-sharing PrO12 cuboctahedra. There are a spread of Pr–O bond distances ranging from 2.62–2.81 Å. In the third Pr3+ site, Pr3+ is bonded in a distorted q6 geometry to eleven O2- atoms. There are a spread of Pr–O bond distances ranging from 2.56–2.77 Å. There are six inequivalent N5+ sites. In the first N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.25 Å) and one longer (1.30 Å) N–O bond length. In the second N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of N–O bond distances ranging from 1.24–1.31 Å. In the third N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.25 Å) and one longer (1.30 Å) N–O bond length. In the fourth N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.25 Å) and one longer (1.30 Å) N–O bond length. In the fifth N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of N–O bond distances ranging from 1.25–1.28 Å. In the sixth N5+ site, N5+ is bonded in a trigonal planar geometry to three O2- atoms. There are a spread of N–O bond distances ranging from 1.25–1.30 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one Pr3+ and one N5+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two Pr3+ and one N5+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to two Pr3+ and one N5+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to one Pr3+ and one N5+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to one Pr3+ and one N5+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to two Pr3+ and one N5+ atom. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to one Pr3+ and one N5+ atom. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to one Pr3+ and one N5+ atom. In the ninth O2- site, O2- is bonded in a distorted single-bond geometry to one Pr3+ and one N5+ atom. In the tenth O2- site, O2- is bonded in a distorted single-bond geometry to two Pr3+ and one N5+ atom. In the eleventh O2- site, O2- is bonded in a distorted single-bond geometry to one Pr3+ and one N5+ atom. In the twelfth O2- site, O2- is bonded in a distorted single-bond geometry to one Pr3+ and one N5+ atom. In the thirteenth O2- site, O2- is bonded in a distorted single-bond geometry to one Pr3+ and one N5+ atom. In the fourteenth O2- site, O2- is bonded in a distorted single-bond geometry to two Pr3+ and one N5+ atom. In the fifteenth O2- site, O2- is bonded in a distorted single-bond geometry to one Pr3+ and one N5+ atom. In the sixteenth O2- site, O2- is bonded in a distorted single-bond geometry to one Pr3+ and one N5+ atom. In the seventeenth O2- site, O2- is bonded in a distorted single-bond geometry to one Pr3+ and one N5+ atom. In the eighteenth O2- site, O2- is bonded in a distorted single-bond geometry to one Pr3+ and one N5+ atom.

36 MATERIALS SCIENCE↗