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At least 1,279 records · Page 71
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Structural insights into the thermal decomposition sequence of barium tetrahydrogenorthotellurate(VI), Ba[H{sub 4}TeO{sub 6}]

The compounds Ba[H{sub 4}TeO{sub 6}] (I), Ba[H{sub 2}TeO{sub 5}] (II), Ba[Te{sub 2}O{sub 6}(OH){sub 2}] (III) and Ba[TeO{sub 4}] (IV) were prepared by application of a diffusion method (I), under hydrothermal conditions (II and III) and from solid state reactions (IV), respectively. Structure analysis on the basis of single crystal X-ray diffraction data revealed novel structure types for (I), (II) and (III) and isotypism of (IV) with PrSbO{sub 4} and LaSbO{sub 4}. Common feature of the four oxotellurate(VI) structures are [TeO{sub 6}] octahedra. Whereas in the crystal structure of (I) the octahedral units are isolated, they are condensed into chains via corner-sharing in (II) and via edge-sharing in (III) and (IV). The coordination numbers of the barium cations in the four structures range from seven to ten. Although hydrogen atom positions could not be located for the structures of (I) and (II), short interpolyhedral O···O contacts are evident for strong hydrogen bonding. The temperature behaviour of (I), (II) and (IV) was monitored by simultaneous thermal analysis (STA) measurements and in situ powder X-ray diffraction, revealing the decomposition sequence Ba[H{sub 4}TeO{sub 6}] → Ba[H{sub 2}TeO{sub 5}] → Ba[TeO{sub 4}]→ Ba[TeO{sub 3}] upon heating to temperatures up to 900 °C. - Graphical abstract: The crystal structures of the four oxotellurates(VI) were determined from single crystal data. The thermal decomposition of Ba[H{sub 4}TeO{sub 6}], monitored by temperature-dependent X-ray powder diffraction and simultaneous thermal analysis measurements, involves two condensation reactions according to Ba[H{sub 4}TeO{sub 6}]→Ba[H{sub 2}TeO{sub 5}]+H{sub 2}O(↑)→Ba[TeO{sub 4}]+ H{sub 2}O(↑). Display Omitted.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

Neutron Diffraction and Magnetic Susceptibility Studies on a High-Voltage Li 1.2 Mn 0.55 Ni 0.15 Co 0.10 O 2 Lithium Ion Battery Cathode: Insight into the Crystal Structure

Lithium- and manganese-rich oxides undergo structural transformation and/or atomic rearrangements during the delithiation/lithiation process and ultimately suffer from several issues such as first cycle irreversible capacity and voltage fade. In order to understand the mechanism of these issues, perception of a detailed crystal structure of pristine material is obviously demanding. In this study, combined powder neutron diffraction (ND) and temperature-dependent magnetic susceptibility techniques were employed to investigate the structure of a pristine lithium- and manganese-rich Li1.2Mn0.55Ni0.15Co0.10O2 cathode oxide. Rietveld refinement on the experimental ND pattern yields good fits by considering either Li2MO3 (M = Co, Mn, Ni) type monoclinic (C2/m space group) phase with 1% of Ni residing in the 4h lithium site or a composite structure consisting of 50% of Li2MnO3 type monoclinic (C2/m space group) and 50% LiMO2 (M = Co, Mn, Ni) type trigonal (R$\bar{3}$m space group) structure. In the composite structure, 3% Li/Ni site exchange in the trigonal phase is also proposed. Further, temperature-dependent dc magnetic susceptibility shows Curie–Weiss paramagnetic behavior at T ≥ 100 K, and no ordering/deviation of the field cooling (FC) curve in the temperature range 2–320 K indicates the random distribution of metal ions in the transition metal (TM) layer in the trigonal phase. Bifurcation of the zero-field cooling (ZFC) curve from the FC curve showing a magnetic ordering at TN 50 K reveals the presence of cation ordering in the TM layers arising from a distinct Li2MnO3-like phase. These results suggest that the lithium- and manganese-rich oxide with a composition Li1.2Mn0.55Ni0.15Co0.10O2 is more likely a composite of monoclinic and trigonal phases. The report also highlights the unique materials diagnostic capability of combined ND and magnetic susceptibility techniques to obtain detailed structural information of complex oxide systems.

Mohanty, Debasish↗
DOE OSTI2017

Accommodating High Transformation Strains in Battery Electrodes via the Formation of Nanoscale Intermediate Phases: Operando Investigation of Olivine NaFePO 4 [Accommodation of High Transformation Strain in Battery Electrodes via Formation of Nanoscale Intermediate Phases: Operando Structure Investigation of Olivine Sodium Iron Phosphate]

Virtually all intercalation compounds used as battery electrodes exhibit significant changes in unit cell volume during use. Na x FePO 4 (0 < x < 1, NFP) olivine, of interest as a cathode for sodium-ion batteries, is a model for topotactic, high strain systems as it exhibits one of the largest discontinuous volume changes (~17% by volume) during its first-order transition between two otherwise isostructural phases. Using synchrotron radiation powder X-ray diffraction (PXD) and pair distribution function (PDF) analysis, we discover a new strain-accommodation mechanism wherein a third, <10 nm scale nanocrystalline phase forms to buffer the large lattice mismatch between primary phases. The new phase has a and b lattice parameters matching one crystalline endmember phase and c lattice parameter matching the other, and is not detectable by powder diffraction alone. Finally, we suggest that this strain-accommodation mechanism may apply to systems with large transformation strains but in which true “amorphization” does not occur.

25 ENERGY STORAGE↗
DOE OSTI2014

Investigation of some new hydro(solvo)thermal synthesis routes to nanostructured mixed-metal oxides

We present a study of two new solvothermal synthesis approaches to mixed-metal oxide materials and structural characterisation of the products formed. The solvothermal oxidation of metallic gallium by a diethanolamine solution of iron(II) chloride at 240 °C produces a crystalline sample of a spinel-structured material, made up of nano-scale particles typically 20 nm in dimension. XANES spectroscopy at the K-edge shows that the material contains predominantly Fe{sup 2+} in an octahedral environment, but that a small amount of Fe{sup 3+} is also present. Careful analysis using transmission electron microscopy and powder neutron diffraction shows that the sample is actually a mixture of two spinel materials: predominantly (>97%) an Fe{sup 2+} phase Ga{sub 1.8}Fe{sub 1.2}O{sub 3.9}, but with a minor impurity phase that is iron-rich. In contrast, the hydrothermal reaction of titanium bis(ammonium lactato)dihydroxide in water with increasing amounts of Sn(IV) acetate allows nanocrystalline samples of the SnO{sub 2}–TiO{sub 2} solid solution to be prepared directly, as proved by powder XRD and Raman spectroscopy. - Graphical abstract: New solvothermal synthesis approaches to spinel and rutile mixed-metal oxides are reported. - Highlights: • Solvothermal oxidation of gallium metal in organic iron(II) solution gives a novel iron gallate spinel. • Hydrothermal reaction of titanium(IV) complex and tin(IV) acetate produces the complete SnO{sub 2}–TiO{sub 2} solid solution. • Nanostructured mixed-metal oxide phases are produced directly from solution.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2024

Venturing into Unexplored Phase Space: Synthesis, Structure, and Properties of MgCo 3 B 2 Featuring a Rumpled Kagomé Network

MgCo 3 B 2 , a novel ternary boride in a previously unexplored phase space, was synthesized using the hydride route. In situ powder X-ray diffraction and DFT calculations aided in the discovery of this compound, whose structure was then determined by single-crystal X-ray diffraction. Like the closely related CeCo 3 B 2 , MgCo 3 B 2 crystallizes in centrosymmetric space group P6/mmm (a = 4.883(2) Å, c = 2.926(2) Å at 210 K, Z = 1). Unlike CeCo 3 B 2 , however, it adopts a disordered structure that features a rumpled Kagomé network of Co atoms, and Mg atoms fill the channels of a Co–B framework. Although the structural disorder leads to motifs that are similar to those observed in MgNi 3 B 2 and other related ternary borides, no evidence of an ordered superstructure was found by single-crystal X-ray diffraction or high-resolution powder X-ray diffraction. In the case of CeCo 3 B 2 , boron atoms occupy the center of regular Co 6 trigonal prisms; in MgCo 3 B 2 , boron atoms are shifted from the center of the prism to form B–B dimers with roughly the same length as those found in MgNi 3 B 2 . Magnetic susceptibility data exhibit an unusual temperature dependence that cannot be convincingly modeled by the modified Curie–Weiss equation, consistent with DFT calculations predicting a nonmagnetic ground state. Intrinsic susceptibility at 300 K is 1.42 × 10 –3 emu/mol Oe, which is comparable to that of paramagnetic YCo 3 B 2 and CeCo 3 B 2 with a similar structure and composition. Here, this study showcases the efficacy of combining several methodologies to discover new solids in unexplored phase spaces. This approach includes in situ PXRD data to monitor reactions of precursors upon heating, a diffusion-enhanced synthesis method, and DFT assessment of compound stability.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

Structure and properties of Na{sub x}M{sub 2}SbO{sub 6}·yH{sub 2}O, M=Co(III), Ni(III) honeycomb oxyhydrates

The oxyhydrates Na{sub 0.85}Co{sub 2}SbO{sub 6}·1.7H{sub 2}O and Na{sub 0.95}Ni{sub 2}SbO{sub 6}·1.5H{sub 2}O were prepared by Br{sub 2} oxidation of Na{sub 3}Co{sub 2}SbO{sub 6} and Na{sub 3}Ni{sub 2}SbO{sub 6} and exposure to ambient air. Their composition and structure are characterized by thermogravimetric analysis, elemental analysis and powder X-ray diffraction. Both form monolayer hydrates with metal cations (Co or Ni) near the 3+ oxidation state. In the parent materials, MO{sub 6} octahedra surround SbO{sub 6} units, forming a honeycomb geometry; Rietveld refinement of the hydrate phases indicate that this motif is retained. Magnetic susceptibility plots display paramagnetic behavior and Curie–Weiss fits support the 3+ oxidation state (low spin d{sup 6}s=0 for Co and low spin d{sup 7}s=1/2 for Ni). Close inspection of the Ni hydrate’s susceptibility reveals a feature at 6.2 K and a non-linear magnetization at 2 K with no saturation up to 9 T. Heat capacity measurements show a large amount of excess entropy in the Ni hydrate in the 2–20 K temperature range, while the heat capacity of the Co hydrate can be described by a simple lattice contribution. The Ni hydrate sample is easily dehydrated by heating above 100 °C and forms a new Na-deficient phase, Na{sub 0.95}Ni{sub 2}SbO{sub 6}, which is stable at room temperature. Magnetic susceptibility of this phase is consistent with the Ni atom remaining in the 3+ oxidation state after dehydration. - Graphical abstract: Powder diffraction patterns of Na{sub 3}Ni{sub 2}SbO{sub 6}, Na{sub 0.95}Ni{sub 2}SbO{sub 6}·1.5H{sub 2}O and Na{sub 0.95}Ni{sub 2}SbO{sub 6}. Each pattern has been normalized in intensity. Cartoons depict the change in layer separation with hydration and give the approximate distances between layers and Ni atoms. Highlights: • New oxyhydrate phases with honeycomb lattices are formed. • Curie–Weiss fits indicate Ni{sup 3+} (s=1/2). • Heat capacity shows a large release of entropy for Ni phase, likely due to a complex magneto-structural phase transition.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

Scaffolds of magnetically active 3d metals in the valence electron controlled borides Ti{sub 9−x}M{sub 2+x}Ru{sub 18}B{sub 8} (M=Cr–Ni; x=0.5–1): Structutral, electronic and magnetic properties

Polycrystalline samples of the boride series Ti{sub 9−x}M{sub 2+x}Ru{sub 18}B{sub 8} (M=Cr, Co, Mn, Ni) including single crystals of Ti{sub 8}Co{sub 3}Ru{sub 18}B{sub 8} have been prepared by arc-melting the elements. The phases were characterized by powder X-ray diffraction (Rietveld refinement), single-crystal X-ray diffraction (for M=Co), and energy-dispersive X-ray (EDX) analysis. They are substitutional variants of the Zn{sub 11}Rh{sub 18}B{sub 8} structure type, space group P4/mbm (No. 127) and contain a “scaffold” structural unit (M-ladders interacting with M/Ti-chains) as well as isolated M/Ti-chains. According to DFT calculations, the Ru–X (X=B, Ti, Ti/M) bonding interactions are nearly constant throughout the series and responsible for the structural stability of these phases, whereas the M–M and Ru–M interactions vary significantly with varying valence electron count. Furthermore, density of states (DOS) analyses predict the phases with M=Mn and Ni to develop a total magnetic moment but not the M=Co phase. Susceptibility measurements confirm the Co phase to be paramagnetic and the Mn Phase orders ferrimagnetically below 120 K and thus develops a magnetic moment, as predicted. - Graphical abstract: The crystal structures of the new phases (M=Cr, Mn, Co, Ni) are confirmed by Rietveld refinement of powder diffraction data and single crystal X-ray diffraction (for M=Co) to contain beside the M-ladder also M/Ti-chains. Similar to the series Ti{sub 9}M{sub 2}Ru{sub 18}B{sub 8}, the crystal structure of the new phases are mainly stabilized by the heteroatomic Ru–B and Ru–Ti bonds that remain nearly constant throughout the series, whereas the M-containing bonds vary significantly with varying valence electron count. An experimental finding confirmed and even extended by COHP bonding analyses. In addition, the DOS analyses of the M-elements reveal the development of magnetic moments for the M=Mn, Ni cases but not for M=Co. Indeed, Ti{sub 8}Co{sub 3}Ru{sub 18}B{sub 8} was found experimentally to be a paramagnet and ferrimagnetic ordering below 120 K is found for M=Mn. Highlights: • Synthesis of the valence electron controlled borides Ti{sub 9−x}M{sub 2+x}Ru{sub 18}B{sub 8} (M=Cr–Ni). • Prediction of magnetic properties of Ti{sub 9−x}M{sub 2+x}Ru{sub 18}B{sub 8}. • Ferrimagnetic ordering found in Ti{sub 8}M{sub 3}Ru{sub 18}B{sub 8}. • Chemical bonding studied by density functional theory.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Low Temperature Phases of Na 2 Ti 3 Cl 8 Revisited

Here, the low temperature phases of Na 2 Ti 3 Cl 8 and their phase transitions were investigated by powder neutron diffraction, heat capacity, and magnetic susceptibility measurements between 1.6 K and room temperature. Aside from the previously known high temperature α-phase ( R 3m) and low temperature γ-phase ( R 3m), a new intermediate temperature β-phase was detected. It has a k = (1/4,1/4,0) superstructure and its molar volume and χT product are half way between the α- and γ-phases. The β-phase is observed between 210 K and 190 K on cooling in powder samples. Its formation is kinetically hindered in crystals. Upon heating the β→α transition occurs at 227 K. From the γ-phase, a γ→α transitions is observed on heating. Only in heat capacity measurements, a shoulder of the peak indicates an intermediate formation of the β-phase. Strong antiferromagnetic interactions between the Ti 2+ ions result in the formation of triangular trimers (Ti 3 clusters). In the γ-phase all Ti 2+ ions are part of trimers. For the β-phase a structural model is proposed, where half of the Ti 2+ ions form trimers. No long-range magnetic order was observed in Na 2 Ti 3 Cl 8 down to 1.6 K.

36 MATERIALS SCIENCE↗
DOE OSTI2016

Single crystal growth of Sr{sub 2}TiMnO{sub 6} by optical floating zone technique

Single crystals of Sr{sub 2}TiMnO{sub 6} were grown by optical floating zone technique. Powder X-ray diffraction studies confirmed the single phase nature of the grown crystal. Laue diffraction studies proved the quality of the grown crystal. Neutron diffraction showed no magnetic ordering down to 6 K. Impedance studies showed temperature dependant relaxation which is due to the presence of oxygen vacancies in the grown crystal.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2013

A new strontium antimonate{sup III} Sr{sub 5}Sb{sub 22}O{sub 38}: Synthesis, crystal structure and characterizations

A new strontium antimonate{sup III}, Sr{sub 5}Sb{sub 22}O{sub 38}, has been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. It crystallizes in the P2{sub 1}/n space group of the monoclinic system with a=11.739(9) Å, b=12.014(10) Å, c=16.412(13) Å, β=91.460(8)°, V=2314.0(3) Å{sup 3}. The crystal structure is built of seven trigonal–pyramidal SbO{sub 3} and four sphenoid SbO{sub 4} polyhedra which are connected through sharing corner-oxygen atoms to form the complex three-dimensional {sub ∞}{sup 3}[Sb{sub 22}O{sub 38}]{sup 10−} anionic network with two different intersectant tunnels along the [111-bar ] and [11-bar 1-bar ] directions accommodating the electric charge balanced Sr{sup 2+} cations. First-principles electronic structure calculations based on the density functional theory (DFT) and the UV–vis diffuse reflectance spectroscopy measurements both indicate that the compound belongs to a direct band insulator with an optical gap value of 3.3 eV. - Graphical abstract: The 2D Sb–O slabs are stacked through sharing oxygen atoms to form the 3D network structure of the new strontium antimonate{sup III} Sr{sub 5}Sb{sub 22}O{sub 38}. - Highlights: • A new strontium antimonate{sup III}, Sr{sub 5}Sb{sub 22}O{sub 38}, has been hydrothermally synthesized. • The single crystal structure was determined by X-ray diffraction. • The powder XRD and UV–vis absorption spectroscopy were studied. • Theoretical studies interpret the relationships between optical absorption and crystal structure.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Chemical Bonding Governs Complex Magnetism in MnPt 5 P

Subtle changes in chemical bonds may result in dramatic revolutions in magnetic properties in solid-state materials. MnPt 5 P, a derivative of the rare-earth-free ferromagnetic MnPt 5 As, was discovered and is presented in this work. Specifically, MnPt 5 P was synthesized, and its crystal structure and chemical composition were characterized by X-ray diffraction as well as energy-dispersive X-ray spectroscopy. Accordingly, MnPt 5 P crystallizes in the layered tetragonal structure with the space group P4/mmm (No. 123), in which the face-shared Mn@Pt 12 polyhedral layers are separated by P layers. In contrast to the ferromagnetism observed in MnPt 5 As, the magnetic properties measurements on MnPt 5 P show antiferromagnetic ordering occurs at ~188 K with a strong magnetic anisotropy in and out of the ab-plane. Moreover, a spin-flop transition appears when a high magnetic field is applied. An A-type antiferromagnetic structure was obtained from the analysis of powder neutron diffraction (PND) patterns collected at 150 and 9 K. Calculated electronic structures imply that hybridization of Mn-3d and Pt-5d orbitals is critical for both the structural stability and observed magnetic properties. Semiempirical molecular orbitals calculations on both MnPt 5 P and MnPt 5 As indicate that the lack of 4p character on the P atoms at the highest occupied molecular orbital (HOMO) in MnPt 5 P may cause the different magnetic behavior in MnPt 5 P compared to MnPt 5 As. The discovery of MnPt 5 P, along with our previously reported MnPt5As, parametrizes the end points of a tunable system to study the chemical bonding which tunes the magnetic ordering from ferromagnetism to antiferromagnetism with the strong spin–orbit coupling (SOC) effect.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2016

The preparation and phase diagrams of ( 7 Li 1-x Fe x OD)FeSe and (Li 1-x Fe x OH)FeSe superconductors

We report the phase diagram for the superconducting system ( 7 Li 1-x Fe x OD)FeSe and contrast it with that of (Li 1-x Fe x OH)FeSe both in single crystal and powder forms. Samples were prepared via hydrothermal methods and characterized by laboratory and synchrotron X-ray diffraction, high-resolution neutron powder diffraction (NPD), and high intensity NPD. We find a correlation between the tetragonality of the unit cell parameters and the critical temperature, Tc, which is indicative of the effects of charge doping on the lattice and formation of iron vacancies in the FeSe layer. We observe no appreciable isotope effect on the maximum Tc in substituting H by D. The NPD measurements definitively rule out an antiferromagnetic ordering in the non-superconducting (Li 1-x Fe x OD)FeSe samples below 120 K, which has been reported in non-superconducting (Li 1-x Fe x OH)FeSe. A likely explanation for the observed antiferromagnetic transition in (Li 1-x Fe x OH)FeSe samples is the formation of impurities during their preparation such as Fe 3 O 4 and Li x FeO 2 , which express a charge ordering transition known as the Verwey transition near 120 K. The concentration of these oxide impurities is found to be dependent on the concentration of the lithium hydroxide reagent and the use of H 2 O vs. D 2 O as the solvent during synthesis. We also describe the reaction conditions that lead to some of our superconducting samples to exhibit ferromagnetism below T c .

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2016

Non-congruence of high-temperature mechanical and structural behaviors of LaCoO 3 based perovskites

Our paper presents the mechanical behavior of LaCoO 3 and La 0.8 Ca 0.2 CoO3 ceramics under four-point bending in which the two cobaltites are subjected to a low stress of ~8 MPa at temperatures ranging from room temperature to 1000 °C. Unexpected stiffening is observed in pure LaCoO 3 in the 700–900 °C temperature range, leading to a significant increase in the measured Young’s modulus, whereas La 0.8 Ca 0.2 CoO 3 exhibits softening from 100 °C to 1000 °C, as expected for most materials upon heating. we use neutron diffraction, X-ray diffraction and micro-Raman spectroscopy to study the crystal structure of the two materials in the RT–1000 °C temperature range. Despite a detailed study, there is no conclusive evidence to explain the stiffening behavior observed in pure LaCoO 3 as opposed to the softening behavior in La 0.8 Ca 0.2 CoO 3 at high temperatures (above 500 °C).

36 MATERIALS SCIENCE↗
DOE OSTI2022

Examination of the cerium α-ε phase transition under dynamic loading with x-ray diffraction

Recent examination of the cerium Hugoniot with pyrometry and x-ray diffraction (XRD) has revealed a narrow solid-liquid two-phase region. It has been suggested that nonequilibrium melting may be occurring along the Ce Hugoniot, with either melt kinetics or a sluggish α-ε transition impeding the transition. In particular, the kinetics of the α-ε is unknown and the location of the phase boundary is in dispute. Static measurements suggest a nearly vertical phase boundary that intersects the Hugoniot at 6–7 GPa. This lies in direct conflict with dynamic measurements along the Hugoniot observing α-Ce through incipient melt. This work presents dynamic experiments using XRD to examine the behavior of the α-ε phase transition. The results show that the α-ε phase transition occurs through a tetragonal distortion, with the transition beginning at temperatures below the solid Hugoniot. Following the initial deviation from an ideal fcc structure, the c/a ratio is found to gradually increase with no steady value observed in the ε phase within the range of these experiments (below 17 GPa). Multiple diffraction patterns captured during the peak stress state show no significant change in c/a ratio prior to uniaxial release, upon which Ce reverts to an fcc structure. Furthermore, the results indicate that the α-ε transition occurs rapidly, both on loading and release. An examination of the c/a ratio with increasing temperatures suggests 11.5 GPa as a lower bound for the location of the α-ε-liquid triple point.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2016

Chemical disorder determines the deviation of the Slater–Pauling rule for Fe 2 MnSi-based Heusler alloys: evidences from neutron diffraction and density functional theory

Fe 2 MnSi fails to follow the Slater–Pauling rule. This phenomenon is thought to originate from either: (i) an antiferromagnetic arrangement of Mn ions at low temperature and/or (ii) chemical disorder. An important insight on this issue could be achieved by considering Fe 2 MnSi 1-x Ga x compounds, thoroughly studied here by means of magnetization, neutron diffraction and density functional calculations (DFT). Our results indicate that chemical disorder (and not the antiferromagnetic arrangement) is responsible for the deviation of the Slater–Pauling rule on Fe 2 MnSi-based Heusler alloys. Furthermore, evidences suggest that Ga substitution into Si site favors the Fe/Mn disorder, further enhancing the observed deviation.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2022

Structure and properties of the Sr 2 In 1-x Sn x SbO 6 double perovskite

A series of n -type oxide double perovskite semiconductors, Sr 2 In 1-x Sn x SbO 6 (0 ≤ x ≤ 0.3) has been synthesized; Sn 4+ partially substitutes for In 3+ . 121 Sb and 119 Sn Mössbauer spectroscopy are employed to investigate the B-site cation ordering because this issue cannot be resolved by conventional diffraction techniques alone. Rigid ordering between In 3+ /Sn 4+ and Sb 5+ sites is revealed by the spectroscopic method, and hence in combination with the structural parameters extracted from the XRD structural refinements, the crystallographic structure of this series of compounds is depicted. Furthermore, the temperature dependent magnetic susceptibilities, band gaps, and carrier type are characterized, and the calculated band structure is presented.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗