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Title: Competing Pathways for Nucleation of the Double Perovskite Structure in the Epitaxial Synthesis of La 2 MnNiO 6

Abstract

Over the past decades a confluence of advanced synthesis techniques, data-driven characterization, and rapid increases in computing power has sparked a renaissance in materials engineering. The emerging “materials-by-design” approach, while radically transforming the development of multicomponent systems, has tended to overlook the complex kinetic pathways that define materials synthesis. Although we are able to envision almost limitless materials combinations, we are unable to synthesize all of them in practice, since existing characterization and modeling approaches often fail to capture the inherent complexity of such systems. There is currently a disconnect between highly local structural characterization and macroscale properties measurements, resulting in oversimplified or incomplete structure-property models. Here we describe a multi-technique approach that combines aberration-corrected transmission electron microscopy with emerging oxide atom probe tomography to measure chemical ordering and extended defects in the model complex oxide, La2MnNiO6. We visualize cation ordering, as well as a three-dimensional network of secondary phases, which we describe in terms of ab initio structure calculations. We propose a defect model in which these phases alter their surrounding octahedral environment, severely disrupting cation superexchange. Through this array of experimental and theoretical techniques, we uncover fundamental structure-property relationships and illustrate a new approach to engineer complex, multicomponentmore » systems.« less

Authors:
; ; ; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1327135
Report Number(s):
PNNL-SA-115671
Journal ID: ISSN 0897-4756; 48341; KC0203020
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Chemistry of Materials; Journal Volume: 28; Journal Issue: 11
Country of Publication:
United States
Language:
English
Subject:
oxide thin films; scanning transmission electron microscopy; atom probe tomography; electron energy loss spectroscopy; density functional theory; Environmental Molecular Sciences Laboratory

Citation Formats

Spurgeon, Steven R., Du, Yingge, Droubay, Timothy, Devaraj, Arun, Sang, Xiahan, Longo, Paolo, Yan, Pengfei, Kotula, Paul G., Shutthanandan, Vaithiyalingam, Bowden, Mark E., LeBeau, James M., Wang, Chongmin, Sushko, Peter V., and Chambers, Scott A. Competing Pathways for Nucleation of the Double Perovskite Structure in the Epitaxial Synthesis of La 2 MnNiO 6. United States: N. p., 2016. Web. doi:10.1021/acs.chemmater.6b00829.
Spurgeon, Steven R., Du, Yingge, Droubay, Timothy, Devaraj, Arun, Sang, Xiahan, Longo, Paolo, Yan, Pengfei, Kotula, Paul G., Shutthanandan, Vaithiyalingam, Bowden, Mark E., LeBeau, James M., Wang, Chongmin, Sushko, Peter V., & Chambers, Scott A. Competing Pathways for Nucleation of the Double Perovskite Structure in the Epitaxial Synthesis of La 2 MnNiO 6. United States. doi:10.1021/acs.chemmater.6b00829.
Spurgeon, Steven R., Du, Yingge, Droubay, Timothy, Devaraj, Arun, Sang, Xiahan, Longo, Paolo, Yan, Pengfei, Kotula, Paul G., Shutthanandan, Vaithiyalingam, Bowden, Mark E., LeBeau, James M., Wang, Chongmin, Sushko, Peter V., and Chambers, Scott A. 2016. "Competing Pathways for Nucleation of the Double Perovskite Structure in the Epitaxial Synthesis of La 2 MnNiO 6". United States. doi:10.1021/acs.chemmater.6b00829.
@article{osti_1327135,
title = {Competing Pathways for Nucleation of the Double Perovskite Structure in the Epitaxial Synthesis of La 2 MnNiO 6},
author = {Spurgeon, Steven R. and Du, Yingge and Droubay, Timothy and Devaraj, Arun and Sang, Xiahan and Longo, Paolo and Yan, Pengfei and Kotula, Paul G. and Shutthanandan, Vaithiyalingam and Bowden, Mark E. and LeBeau, James M. and Wang, Chongmin and Sushko, Peter V. and Chambers, Scott A.},
abstractNote = {Over the past decades a confluence of advanced synthesis techniques, data-driven characterization, and rapid increases in computing power has sparked a renaissance in materials engineering. The emerging “materials-by-design” approach, while radically transforming the development of multicomponent systems, has tended to overlook the complex kinetic pathways that define materials synthesis. Although we are able to envision almost limitless materials combinations, we are unable to synthesize all of them in practice, since existing characterization and modeling approaches often fail to capture the inherent complexity of such systems. There is currently a disconnect between highly local structural characterization and macroscale properties measurements, resulting in oversimplified or incomplete structure-property models. Here we describe a multi-technique approach that combines aberration-corrected transmission electron microscopy with emerging oxide atom probe tomography to measure chemical ordering and extended defects in the model complex oxide, La2MnNiO6. We visualize cation ordering, as well as a three-dimensional network of secondary phases, which we describe in terms of ab initio structure calculations. We propose a defect model in which these phases alter their surrounding octahedral environment, severely disrupting cation superexchange. Through this array of experimental and theoretical techniques, we uncover fundamental structure-property relationships and illustrate a new approach to engineer complex, multicomponent systems.},
doi = {10.1021/acs.chemmater.6b00829},
journal = {Chemistry of Materials},
number = 11,
volume = 28,
place = {United States},
year = 2016,
month = 6
}
  • The synthesis, structural characterization, and magnetic properties of La{sub 3}Co{sub 2}SbO{sub 9} double perovskite are reported. The crystal structure has been refined by X-ray and neutron powder diffraction data in the monoclinic space group P2{sub 1}/n. Co{sup 2+} and Sb{sup 5+} have the maximum order allowed for the La{sub 3}Co{sub 2}SbO{sub 9} stoichiometry. Rietveld refinements of powder neutron diffraction data show that at room temperature the cell parameters are a=5.6274(2) A, b=5.6842(2) A, c=7.9748(2) A and {beta}=89.999(3) Degree-Sign . Magnetization measurements indicate the presence of ferromagnetic correlations with T{sub C}=55 K attributed to the exchange interactions for non-linear Co{sup 2+}-O-Sb{supmore » 5+}-O-Co{sup 2+} paths. The effective magnetic moment obtained experimentally is {mu}{sub exp}=4.38 {mu}{sub B} (per mol Co{sup 2+}), between the theoretical one for spin only (3.87 {mu}{sub B}) and spin-orbit value (6.63 {mu}{sub B}), indicating partially unquenched contribution. The low magnetization value at high magnetic field and low temperature (1 {mu}{sub B}/f.u., 5 T and 5 K) and the difference between ZFC and FC magnetization curves (at 5 kOe) indicate that the ferromagnetism do not reach a long range order and that the material has an important magnetic frustration. - Graphical abstract: Co-O-Co (Yellow octahedra only) rich zones (antiferromagnetic) are in contact with Co-O-Sb-O-Co (Red and yellow octahedra) rich zones (Ferromagnetic) to give the peculiar magnetic properties, as a consequence, a complex hysteresis loop can be observed composed by a main and irreversible curve in all the measured range, superimposed with a ferromagnetic component at low fields. Highlights: Black-Right-Pointing-Pointer La{sub 3}Co{sub 2}SbO{sub 9} has small Goldschmidt Tolerance Factor (t) due to the small size of La{sup 3+}. Black-Right-Pointing-Pointer Small t determines an angle for the path Co{sup 2+}-O-Sb{sup 5+}-O-Co{sup 2+} of 153 Degree-Sign . Black-Right-Pointing-Pointer Ferromagnetism is attributed to exchange interactions for Co{sup 2+}-O-Sb{sup 5+}-O-Co{sup 2+} paths. Black-Right-Pointing-Pointer Ferromagnetic nanoclusters are embedded in an antiferromagnetic matrix.« less
  • The synthesis, structural characterization, and magnetic property studies of SrLaMnSbO6 double perovskite oxide are reported. The crystal structure of SrLaMnSbO6 has been solved by powder X-ray (PXD) and neutron diffraction (NPD) data in the monoclinic space group P21/n (a = 5.6878(3) Angstroms, b = 5.6990(2) Angstroms, c = 8.0499(4) Angstroms and {beta} = 89.98(2); 295 K, NPD data). The Mn and Sb atoms are nearly completely ordered over the B-site of the perovskite structure. The octahedral framework displays significant tilting distortion according to the Glazer's tilt system a-a-c+. X-ray absorption near-edge spectroscopic (XAS) studies show the presence of Mn2+ andmore » Sb5+ formal oxidation states. The magnetic susceptibility data of SrLaMnSbO6 indicate the presence of ferromagnetic correlations; the calculated effective paramagnetic moment, {mu}calcd = 5.92 {mu}B (for HS Mn2+(3d5), S = 5/2; as evidenced by XAS data) is in good agreement with the value obtained experimentally ({mu}exp = 5.70 {mu}B). Variable temperature neutron diffraction data show no evidence of structural transition down to 3.7 K. A long-range antiferromagnetic ordering is established at TN = 8 K as evidenced by the magnetic susceptibility and specific heat measurements. The magnetic structure at 3.7 K is characterized by k = 0 propagation vector and m1x = -m2x, m1y = m2y = 0, m1z = -m2z (mx = 1.26(7) {mu}B, mz = 1.82(6) {mu}B) coupling of magnetic moments on the Mn1 (1/2,0,0) and Mn2 (0,1/2,1/2) atoms with the ordered magnetic moment of 2.21(4) {mu}B.« less
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