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Title: Identification of Mn site in Pb(Zr,Ti)O{sub 3} by synchrotron x-ray absorption near-edge structure: Theory and experiment

Abstract

Synchrotron x-ray absorption near-edge structure (XANES) experiments are performed on Mn-doped PbZr{sub 1-x}Ti{sub x}O{sub 3} samples (PZT) and compared with first-principles XANES simulations. The features of the measured Mn K-edge XANES are consistent with the first-principles XANES of Mn on the Ti/Zr site and inconsistent with Mn on other sites. The clear agreement between measured and first-principles theoretical XANES spectra reported here is by far the strongest evidence of Mn substituting for Ti/Zr in PZT. This work illustrates that a first-principles supercell framework, which is popularly used to study impurities in crystals, can be used in conjunction with XANES measurement in order to identify an impurity structure with a high degree of confidence. This approach may thus be broadly applicable to study impurities in other crystals.

Authors:
; ; ; ;  [1];  [2];  [2]
  1. National Synchrotron Research Center, Nakhon Ratchasima 30000, Thailand and School of Physics, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand)
  2. (Thailand)
Publication Date:
OSTI Identifier:
20971868
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 90; Journal Issue: 10; Other Information: DOI: 10.1063/1.2711200; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ABSORPTION; ABSORPTION SPECTROSCOPY; CRYSTALS; DOPED MATERIALS; IMPURITIES; MANGANESE; PZT; SYNCHROTRONS; X-RAY SPECTROSCOPY

Citation Formats

Limpijumnong, Sukit, Rujirawat, Saroj, Boonchun, Adisak, Smith, M. F., Cherdhirunkorn, B., National Synchrotron Research Center, Nakhon Ratchasima 30000, and Department of Physics, Thammasat University, Patum Thani 12121. Identification of Mn site in Pb(Zr,Ti)O{sub 3} by synchrotron x-ray absorption near-edge structure: Theory and experiment. United States: N. p., 2007. Web. doi:10.1063/1.2711200.
Limpijumnong, Sukit, Rujirawat, Saroj, Boonchun, Adisak, Smith, M. F., Cherdhirunkorn, B., National Synchrotron Research Center, Nakhon Ratchasima 30000, & Department of Physics, Thammasat University, Patum Thani 12121. Identification of Mn site in Pb(Zr,Ti)O{sub 3} by synchrotron x-ray absorption near-edge structure: Theory and experiment. United States. doi:10.1063/1.2711200.
Limpijumnong, Sukit, Rujirawat, Saroj, Boonchun, Adisak, Smith, M. F., Cherdhirunkorn, B., National Synchrotron Research Center, Nakhon Ratchasima 30000, and Department of Physics, Thammasat University, Patum Thani 12121. Mon . "Identification of Mn site in Pb(Zr,Ti)O{sub 3} by synchrotron x-ray absorption near-edge structure: Theory and experiment". United States. doi:10.1063/1.2711200.
@article{osti_20971868,
title = {Identification of Mn site in Pb(Zr,Ti)O{sub 3} by synchrotron x-ray absorption near-edge structure: Theory and experiment},
author = {Limpijumnong, Sukit and Rujirawat, Saroj and Boonchun, Adisak and Smith, M. F. and Cherdhirunkorn, B. and National Synchrotron Research Center, Nakhon Ratchasima 30000 and Department of Physics, Thammasat University, Patum Thani 12121},
abstractNote = {Synchrotron x-ray absorption near-edge structure (XANES) experiments are performed on Mn-doped PbZr{sub 1-x}Ti{sub x}O{sub 3} samples (PZT) and compared with first-principles XANES simulations. The features of the measured Mn K-edge XANES are consistent with the first-principles XANES of Mn on the Ti/Zr site and inconsistent with Mn on other sites. The clear agreement between measured and first-principles theoretical XANES spectra reported here is by far the strongest evidence of Mn substituting for Ti/Zr in PZT. This work illustrates that a first-principles supercell framework, which is popularly used to study impurities in crystals, can be used in conjunction with XANES measurement in order to identify an impurity structure with a high degree of confidence. This approach may thus be broadly applicable to study impurities in other crystals.},
doi = {10.1063/1.2711200},
journal = {Applied Physics Letters},
number = 10,
volume = 90,
place = {United States},
year = {Mon Mar 05 00:00:00 EST 2007},
month = {Mon Mar 05 00:00:00 EST 2007}
}
  • The structural and electronic properties of Gd{sub 2}(Ti{sub 1-y}Zr{sub y}){sub 2}O{sub 7} (y=0-1) pyrochlores following a 2.0-MeV Au{sup 2+} ion-beam irradiation ({approx}5.0x10{sup 14} Au{sup 2+}/cm{sup 2}) have been investigated by Ti 2p and O 1s near-edge x-ray absorption fine structure (NEXAFS). The irradiation of Gd{sub 2}(Ti{sub 1-y}Zr{sub y}){sub 2}O{sub 7} leads to the phase transformation from the ordered pyrochlore structure (Fd3m) to the defect fluorite structure (Fm3m) regardless of Zr concentration. Irradiated Gd{sub 2}(Ti{sub 1-y}Zr{sub y}){sub 2}O{sub 7} with y{<=}0.5 are amorphous, although significant short-range order is present. Contrasting to this behavior, compositions with y{>=}0.75 retain crystallinity in the defectmore » fluorite structure following irradiation. The local structures of Zr{sup 4+} in the irradiated Gd{sub 2}(Ti{sub 1-y}Zr{sub y}){sub 2}O{sub 7} with y{>=}0.75 determined by NEXAFS are the same as in the cubic fluorite-structured yttria-stabilized zirconia (Y-ZrO{sub 2}), thereby providing conclusive evidence for the phase transformation. The TiO{sub 6} octahedra present in Gd{sub 2}(Ti{sub 1-y}Zr{sub y}){sub 2}O{sub 7} are completely modified by ion-beam irradiation to TiO{sub x} polyhedra, and the Ti coordination is increased to eight with longer Ti-O bond distances. The similarity between cation sites and the degree of disorder in Gd{sub 2}Zr{sub 2}O{sub 7} facilitate the rearrangement and relaxation of Gd, Zr, and O ions/defects. This inhibits amorphization during the ion-beam-induced phase transition to the radiation-resistant defect fluorite structure, which is in contrast to the ordered Gd{sub 2}Ti{sub 2}O{sub 7}.« less
  • This paper reports on the structural characterization of Pb{sub 1−x}Ba{sub x}Zr{sub 0.40}Ti{sub 0.60}O{sub 3} (PBZT) ferroelectric ceramic compositions prepared by the conventional solid state reaction method. X-ray absorption spectroscopy (XAS) and Raman spectroscopy were used in the probing of the local structure of PBZT samples that exhibit a normal or relaxor ferroelectric behavior. They showed a considerable local disorder around Zr and Pb atoms in the samples of tetragonal or cubic long-range order symmetry. The intensity of the E(TO{sub 3}) mode in the Raman spectra of PBZT relaxor samples remains constant at temperatures lower than T{sub m}, which has provenmore » the stabilization of the correlation process between nanodomains. - Graphical abstract: X-ray absorption measurements showed considerable local disorder around Zr and Pb atoms in the samples of tetragonal or cubic long-range order symmetry. The intensity of the E(TO{sub 3}) mode in the Raman spectra of PBZT relaxor samples remains constant at temperatures lower than T{sub m}, which has proven the stabilization of the correlation process between nanodomains. Display Omitted - Highlights: • Structural characterization of Pb{sub 1−x}Ba{sub x}Zr{sub 0.40}Ti{sub 0.60}O{sub 3} (PBZT) ferroelectric ceramic. • X-ray absorption and Raman spectroscopies were used to probe the structure of PBZT. • Dissymmetry of Zr and Pb sites was observed in samples long-range cubic symmetry. • Local disorder in all PBZT samples through the observation of Raman active modes.« less
  • Disorder in Gd{sub 2}Ti{sub 2}O{sub 7} is investigated by near-edge x-ray absorption fine structure (NEXAFS) and x-ray photoelectron spectroscopy (XPS). NEXAFS shows Ti{sup 4+} ions occupy octahedral sites with a tetragonal distortion induced by vacant oxygen sites. O 1s XPS spectra obtained with a charge neutralization system from Gd{sub 2}Ti{sub 2}O{sub 7} (100) and the Gd{sub 2}Ti{sub 2}O{sub 7} pyrochlore used in Phys. Rev. Lett. 88, 105901 (2002), both yielded a single peak, unlike the previous result on the latter that found two peaks. The current results give no evidence for an anisotropic distribution of Ti and O. The extramore » features reported in the aforementioned communication resulted from charging effects and incomplete surface cleaning. Thus, a result confirming the direct observation of simultaneous cation-anion antisite disordering and lending credence to the split vacancy model has been clarified.« less
  • An alcoholysis exchange between tris(hydroxymethyl)ethane (THME-H{sub 3}) or tris(hydroxymethyl)propane (THMP-H{sub 3}) and group IV metal isopropoxides yields compounds of the general formula (THMR){sub 2}M{sub 4}(OCHMe{sub 2}){sub 10}[M = Ti (R = E, 1; P, 2); Zr (R = E, 3; P, 4)]. 1 and 2 are formed in toluene, at ambient glovebox temperatures, and adopt a typical fused-M{sub 3}O{sub 12} structure where each titanium atom is surrounded by six oxygens in a slightly distorted face-shared bioctahedral arrangement. All of the oxygens of the central core are from the THMR ligand, present as {mu}-O and {mu}{sub 3}-O oxygen bridges. Generation ofmore » 3 or 4 requires heating in toluene at reflux temperatures. The zirconium atoms of 3 possess an extremely distorted edge-shared bioctahedral geometry where the central core consists of a Zr{sub 4}O{sub 8} ring (eight oxygens: six from THME ligands and two from isopropoxide ligands). Each of the zirconium atoms is six-coordinated with four bridging oxygens and two terminal isopropoxide ligands. Spincast deposited films generated from toluene solutions of 1 and 3 indicate that increased uniformity of the films and decreased hydrolysis occur in comparison to the cases of Ti(OCHMe{sub 2}){sub 4}, 5, and [Zr(OCHMe{sub 2}){sub 4}{center_dot}HOCHMe{sub 2}]{sub 2}, 6, respectively.« less
  • X-ray absorption near-edge spectroscopic (XANES) measurements of the Fe and Co K-edges for a series of Brownmillerite-type transition-metal oxides (A{sub 2}B{prime}{sub x}B{sub 2-x}O{sub 5}; A = Ca, Sr; B{prime}/B = Al, Mn, Fe, Co) have been made. In these compounds, the metal atoms are present in both octahedral and tetrahedral coordination environments. The spectra were interpreted with the aid of electronic structure calculations. Significant changes in intensity and energy were observed in the Fe K-edge spectra as the average Fe{sup 3+} coordination number (CN) was changed from 5.5 (Ca{sub 2}AlFeO{sub 5}) to 4.2 (Ca{sub 2}FeMnO{sub 5}). In Ca{sub 2}Co{sub x}Fe{submore » 2-x}O{sub 5}, the Fe K- and Co K-edge XANES spectra indicated that Fe has a slight octahedral site preference in these series. This confirmed that size effects play a significant role in controlling the site preference of metal atoms in these compounds. The change in the average Fe CN with Co substitution was examined by analysis of a 3D plot, which compared all of the changes observed in the spectra. This type of analysis gives an accurate depiction of the change in Fe CN as compared to standard materials. The Fe K-edge peak intensities in Ca{sub 2-y}Sr{sub y}Fe{sub 2}O{sub 5} decreased with higher values of y, a result of decreased Fe 4p(3d)-O 2p overlap with increasing Sr concentration.« less