Realizar estudos de óxidos com estrutura perovskita La1-xAxCoO3 dopadas com Bário e
Cálcio com x=0,2, usando a técnica Pechini na preparação dessas estruturas policristalinas. A técnica utilizada para investigar essas estruturas na faixa de temperatura entre 50 K a 298 K será a espectroscopia de absorção de raios X (XAS) na borda K do cobalto. Estas análises nesses materiais têm como finalidade observar se a estrutura La1-xAxCoO3 dopadas Ba e Ca em função
de temperatura mostram as mesmas características estruturais nessas amostras em relação aos estudos desenvolvidos neste trabalho com a técnica de combustão. Assim como também, verificar se as anomalias apresentadas na estrutura La0,8Ba0,2CoO3 nas temperaturas 220 K e 260
K são características intrínseca desse material, ou surgem dos diferentes métodos de preparação dessas amostras. Propõe-se, também, estudar mais detalhadamente na região XANES, através de estudos teóricos quantitativos, as transições de spin nas estruturas La0,8Ba0,2CoO3 e
La0,8Ca0,2CoO3 em função de temperatura sintetizadas pelas técnicas combustão e Pechinni.
Outra possibilidade de trabalho futuro é estudar as propriedades magnéticas dessas amostras para possível aplicação futura.
REFERÊNCIAS
1 JONKER, G. H.; VAN SANTEN, J. H. Magnetic Compounds with Perovskite Structure III. Ferromagnetic Compounds of Cobalt. Physica (Amsterdam), v. 19, p. 120-130, 1953. 2 KOEHLER, W. C; WOLLAN, E. O. Neutron-Diffraction Study of the Magnetic Properties of Perovskite-Like Compounds LaBO3. Journal of Physics and Chemistry of Solids, v. 2, p.
100-106, 1957. Disponível em:< http://www.sciencedirect.com> Acesso em: 14 abr. 2011. 3 GOODENOUGH, J. B. An interpretation of the Magnetic Properties of the Perovskite-Type Mixed Crystals. Journal of Physics and Chemistry of Solids, v. 6, p. 287-297, 1958. Disponivel em:< http://www.sciencedirect.com> Acesso em: 14 Abr. 2011.
4 KOROTIN, M. A, et al. Intermediate-Spin state and Properties of LaCoO3. Physical Review B,
v. 54, n. 8, p. 5309- 5316, 1996. Disponível em: < http://prb.aps.org> Acesso em: 20 Mar. 2011.
5 YAMAGUCHI, S; OKIMOTO, Y; TOKURA , Y. Local Lattice Distortion during the Spins- State transition in LaCoO3. Physical Review B, v.55, n. 14, p. R8666-R8669, 1997. Disponível
em: < http://prb.aps.org> Acesso em: 24 Mar. 2011.
6 ZOBEL, C, et al. Evidence for a low-spin to intermediate-spin state transition in LaCoO3. Physical Review B, v. 66, n.2, p. 020402-02402-4, 2002. Disponível em: < http://prb.aps.org> Acesso em: 24 Mar. 2011.
7 KLIE, R. F, et al. Leighton. Direct Measurement of the Low-Temperature Spin-State Transition in LaCoO3. Physical Review Letters, v. 99, p. 047203- 047203-4, 2007. Disponivel em: < http://prb.aps.org> Acesso em: 24 Mar. 2011.
8 LAREF, A;SEKKAL, W. First-principle calculations of anomalous spin-state excitation in LaCoO3. Materials Chemistry and Physics, v. 123, p. 125–131, 2010. Disponível
em:< http://www.sciencedirect.com> Acesso em: 10 Ago. 2011
9 RACCAH, P. M; GOODENOUGH, J. B. First-Order Localized-Electron ⇆Collective-Electron Transition in LaCoO3. Physical Review, v. 155, n. 3, p. 932-943, 1967. Disponível em: <
http://prb.aps.org> Acesso em: 12 Maio. 2011.
10 YAMAGUCHI, S, et al. Spin-state Transition and High-Spin Polarons in LaCoO3. Physical
Review B, v. 53, n. 6, p. R2926–R2929, 1996. Disponível em: ˂http:// prb.aps.org> Acesso em: 15 Maio 2011.
11 HAVERKORT, M.W, et al. Spin State Transition in LaCoO3 Studied Using Soft X-ray Absorption Spectroscopy and Magnetic Circular Dichroism. Physical Review Letters,v. 97, p. 176405- 176405-4, 2006. Disponível em: ˂http:// prb.aps.org> Acesso em: 10 Maio 2011.
12 HSU, H.;BLAHA, P; WENTZCOVITCH, R. M. Ferromagnetic Insulating State in Tensile- Strained LaCoO3 Thin Films from LDA+U Calculations. Physical Review B, v. 85, p.
140404- 140404-5, 2012. Disponivel em: ˂http:// prb.aps.org> Acesso em: 12 Dez. 2012. 13 KELL, S; TANASE, M; KLIE, R.F. Study of Ferroelastic Behavior and Microstructure in Polycrystalline LaCoO3 using Transmission Electron Microscopy. Journal of
Undergraduate Research, v. 3, p. 1-5, 2010.
14 EFIMOVA, E, et al. Short- and long-range order in La1_xSrxCoO3 and La1_xBaxCoO3. Journal of Physics and Chemistry of Solids, v. 69, n.9, p. 2187-2190, 2008. Disponível em:< http://www.sciencedirect.com> Acesso em: 15 Mar. 2011.
15 ROYER, S; DUPREZ, D; KALIAGUINE, S. Oxygen Mobility in LaCoO3 Perovskites, Catalysis Today, v. 112 p. 99–102, 2006. Disponível
em:< http://www.sciencedirect.com> Acesso em: 15 Mar. 2011.
16 COLONNA, S, et al. Zirconia Supported La, Co oxides and LaCoO3 perovskite: Structural Characterization and Catalytic CO Oxidation. Journal of Molecular Catalysis A: Chemical, v. 180, p. 161–168, 2002. Disponível em:< http://www.sciencedirect.com> Acesso em: 15 Mar. 2011
17 MEHTA, V. V,et al. Ferromagnetism in Tetragonally Distorted LaCoO3 Thin Films, Journal of Applied Physics, v.105, p. 07E503 – 07E503-3, 2009. Disponível em: ˂
http://scitation.aip.org/content/aip/journal/jap> Acesso em: 10 Abr. 2010.
18 FUCHS, D, et al. Ferromagnetic Order in Epitaxially Strained LaCoO3 Thin Films. Physical Review B, v. 75, 144402-144402-5, 2007. Disponível em: ˂http:// prb.aps.org> Acesso em: 10 Dez. 2011.
19 MERZ, M,et al. Schuppler. X-ray Absorption and Magnetic Circular Dichroism of LaCoO3, La0.7Ce0.3CoO3, and La0.7Sr0.3CoO3 Films: Evidence for Cobalt-Valence-Dependent Magnetism. Physical Review B, v. 82, p. 174416 - 174416-9, 2010. Disponível em: ˂http:// prb.aps.org> Acesso em: 10 Dez 2012.
20 KRIENER, M, et al. Structure, magnetization, and resistivity of La1-xMxCoO3 (M=Ca, Sr, and
Ba). Physical Review B, v. 69, p. 094417 – 094417-7, 2004. Disponivel em: ˂http:// prb.aps.org> Acesso em: 10 Dez. 2012.
21 WANG, Y, et al. Correlation between the Structural Distortions and Thermoelectric
Characteristics in La1-xAxCoO3 (A = Ca and Sr). Inorganic Chemistry, v.49, p. 3216–3223,
22 RADAELLI, P. G; CHEONG, S. W. Structural phenomena associated with the spin-state transition in LaCoO3. Physical Review B, v. 66, p. 094408 – 094408-9, 2002. Disponível em: ˂http://prb.aps.org> Acesso em: 12 Dez. 2011.
23 THORNTON, G; TOFIELD, B. C; HEWAT, A. W. A Neutron diffraction study of LaCoO3 in
the Temperature Range 4.2<T˂1248K. Journal of Solid State Chemistry, v. 61, p. 301-307, 1986. Disponível em:< http://www.sciencedirect.com> Acesso em: 12 Ago. 2011
24 MARIS, G, et al. Evidence for orbital ordering in LaCoO3. Physical Review B, v.67, p. 224423-224423-5, 2003. . Disponível em: ˂http://prb.aps.org> Acesso em: 12 Dez. 2011. 25 TAKAMI, T, et al. Correlation between the structure and the spin state in R1−xSrxCoO3
(R=La, Pr, and Nd). Physical Review B, v. 76, p. 144116 – 144116-7, 2007. Disponível em: ˂http://prb.aps.org> Acesso em: 12 Dez. 2011.
26 SEVILLANO, E; MEUTH, H; REHR, J. J. Extended x-ray absorption fine structure Debye- Waller factors. I. Monatomic crystals. Physical Review B, v. 20, p. 4908-4911, 1979. . Disponível em: ˂http://prb.aps.org> Acesso em: 12 Dez. 2011.
27 VACCARI, M; FORNASINI, P. Einstein and Debye models for EXAFS parallel and
perpendicular mean-square relative displacements. Journal of Synchrotron Radiation, v.13, p. 321–325, 2006. Disponível em: ˂ http://journals.iucr.org/s/> Acesso em: 20 Jan. 2010. 28 MACHADO, K. D. Comparison between Einstein and Debye models for an amorphous
Ni46Ti54 alloy produced by mechanical alloying investigated using extended x-ray absorption
fine structure and cumulant expansion. The Journal of Chemical Physics, v.134, p. 064503- 064503-9, 2011. Disponível em: ˂ http://scitation.aip.org/content/aip/journal/jcp> Acesso em: 25 Jan. 2012.
29 REHR, J.J; ALBERS, R.C. Theoretical approaches to x-ray absorption fine structure. Reviews of Modern Physics, v. 72 p. 621-652, 2000. . Disponível em: ˂http://prb.aps.org> Acesso em: 12 Dez. 2011.
30 RAVEL, B. A practical introduction to multiple scattering theory. Journal of Alloys and Compounds, v. 401, n. 1-2. p. 118-126, 2005. Disponivel em:
<http://www.sciencedirect.com> Acesso em: 20 jul. 2008.
31 AMBROSIO, R. C; TICIANELLI, E. A. Electrochemical and X-ray absorption spectroscopy studies of cobalt coatings on a hydrogen storage alloy. Journal of the Electrochemical Society, v. 150, n. 9, p. E438-E443, 2003. Disponível em ˂ http://jes.ecsdl.org/> Acesso em: 22 Ago. 2008.
32 KUZMIN, A, et al. Interpretation of the Co K-edge EXAFS in LaCoO3 using molecular dynamics simulations. Solid State Ionics, Solid State Ionics, v.188, p. 21–24, 2011. 33 COEY, J. M. D; VIRET, M; MOLNAR, S. V. Mixed-valence manganites,
Advances in Physics, v. 48, n. 2, p. 167 -293, 1999. Disponível em: ˂ http://www.tandfonline.com/toc/tadp20/current> Acesso em: 20 Abr. 2011.
34 MEGAW, H. D. Crystal structure of double oxides of the perovskite type. Proceedings of the Physical Society, v. 58, p. 133–152, 1946. Disponível em: ˂http://iopscience.iop.org>,
Acesso em: 20 Abr. 2011.
35 CARNEIRO, A. S. Localização de corrente e efeito joule em manganitas com ordenamento de carga. 2005. 142 f. Tese (doutorado em ciência na área de Física)- Universidade de São Paulo, São Paulo, 2005.
36 MEDARDE, M, et al. Low-temperature spin-state transition in LaCoO3 investigated using resonant x-ray absorption at the Co K edge. Physical Review B, v.73, p.054424- 054424-10, 2006. Disponível em: ˂http://prb.aps.org> Acesso em: 10 Abr. 2011.
37 TOULEMONDE, O, et al. Spin state transition in LaCoO3 with temperature or strontium doping as seen by XAS. Journal of Solid State Chemistry, v. 158, p.208-217, 2001. Disponível em: <http://www.sciencedirect.com> Acesso em: 20 Mar. 2011.
38 ITOH, M, et al.Spin-Glass Behavior and Magnetic Phase Diagram of La1-xSrxCoO3( 0 ≤x
≤0.5) Studied by Magnetization Measurements. Journal of the Physical Society. Japan v. 63, p. 1486-1493, 1994. Disponível em: ˂ http://jpsj.ipap.jp/archive/> Acesso em: 16 Jan. 2011.
39 SATHEY, V. G, et al. Neutron diffraction studies of perovskite-type compounds
La1−xSrxCoO3 (xD 0.1, 0.2, 0.3, 0.4, 0.5). Journal of Physical: Condensed Matter, v.8, p. 3889–3896, 1996.
40 AMBROSIO, R. C. Estudo dos efeitos do tratamento superficial sobre as propriedades eletroquímicas, eletrônicas e estruturais em ligas de hidreto metálico. 2004.119 f. Tese (Doutorado em Físico-Química) – Universidade de São Carlos, São Paulo, 2004.
41 MCBREEN, J. In situ synchrotron techniques in electrochemistry. In: RUBINSTEIN, I. Physical Electrochemistry: principles, methods, and applications. New York: Marcel Dekker, 1995. p. 251-259.
42 BOWRON, D. T; DÍAZ-MORENO, S. Analysis of time-resolved energy-dispersive X-ray absorption spectroscopy data for the study of chemical reaction intermediate states. Analytical chemistry, v. 77, n. 19, p. 6445–6452, 2005. Disponivel em: <pubs.acs.org > Acesso em: 12 Ago. 2010.
43 DÍAZ-MORENO, S; KONINGSBERGER, D. C; MUÑOZ-PÁEZ, A. The “invisible” metal particles in catalysis. Nuclear Instruments and Methods in Physics Research B, v. 133, n. 1-4. p. 15-23. 1997. Disponivel em:< http://www.sciencedirect.com> Acesso em: 26 Abr. 2010.
44 KONINGSBERGER, D. C; PRINS, R. (eds). X-ray absorption: principles, applications, techniques of EXAFS and XANES. New York: John Wiley, 1988. p. 573-663.
45 PENNER-HAHN, J. E. X-ray absorption spectroscopy coordination chemistry. Coordination Chemistry Reviews, v. 190-192, p. 1101-1123, 1999. Disponível em:
<http://www.sciencedirect.com> Acesso em: 20 Mar. 2011.
46 CEZAR, J. C; VICENTIN, F. C; TOLENTINO, H. C. N. Aplicação de técnicas de absorção de raios X no estudo de materiais magnéticos. Revista Brasileira de Ensino de Física, v. 22, n. 3, 2000.
47 RESSLER, T, et al. Quantitative speciation of Mn-Bearing particulates emitted from autos burning (methylcyclopentadienyl)manganese tricarbonyl-added gasolines using XANES spectroscopy. Environmental Science and Technology, v. 34, n. 6, p. 950-958, 2000. Disponivel em: <pubs.acs.org > Acesso em: 20 Abr. 2010.
48 WATANABE, N; MORAIS, J; ALVES, M. C. M. Chemical environment of copper aggregates embedded in polypyrrole films: the nature of the copper-polypyrrole interation. The Journal of Physical Chemistry B, v. 106, n. 43, p.11102-11107, 2002. Disponivel em: <pubs.acs.org > Acesso em: 20 Mar. 2011.
49 CHANG, P.C, et al. XAS study of the residual copper after desorption from rice husk ash. Journal of Spectroscopy and Related Phenomena, v. 156-158, p. 224-227, 2007.
Disponivel em:< http://www.sciencedirect.com> Acesso em: 20 Abr. 2010.
50 YEE, H. S; ABRUÑA, H. D. In-situ X-ray studies of the underpotential deposition of copper on platinum(111). The Journal of Physical Chemistry, v. 97, p. 6278– 6288, 1993. Disponivel em: <pubs.acs.org > Acesso em:14 Jan. 2011.
51 Rehr, J. J, et al. Theoretical X-ray absorption fine structure standards. Journal of the American chemical society, v. 113, n. 14, p. 5135-5140, 1991. Disponivel em: <pubs.acs.org
> Acesso em: 12 Abr. 2011.
52 Ravel, B. EXAFS Analysis FEFF and FEFFIT, http://leonardo.phys.washington.edu/~ ravel/courso/notes.pdf, version 0.05, april 12, 2001.
53 FULTON , J. L, et al. Copper(I) and Copper(II) coordination structure under hydrothermal conditions at 325 °C: An X-ray absorption fine structure and molecular dynamics Study, The Journal of Physical Chemistry A,v. 104, p. 11651-11663, 2002. Disponível em ˂http://pubs.acs.org> Acesso em: 14 Jan. 2009.
54 BARROS, B. S. Reforma a seco e a vapor do metano sobre os precursores catalíticos LaNiO3/α-Al2O3 e La2NiO4/α-Al2O3 preparados por autocombustão assistida por microondas. 2009. 190 f. Tese (Doutorado em Ciência e Engenharia de Materiais) - Programa de Pós-Graduação em Ciência e Engenharia de Materiais, Universidade Federal do Rio
Grande do Norte, Natal, 2009.
55 JAIN, S. R; ADIGA, K. C; VERNEKER , V. P. A new approach to thermo chemical
calculations of condensed fuel – oxidizer mixture. Combustion and Flame, v. 40, p. 71-79, 1981. Disponível em: <http://www.sciencedirect.com> Acesso em: 24 Mar. 2010.
56 NEWVILLE, M. IFEFFIT: interactive XAFS analysis and FEFF fitting, Journal of
Synchrotron Radiation, v.8, p. 322–324, 2001. . Disponível em: ˂ http://journals.iucr.org/s/> Acesso em: 20 Jan. 2010.
57 ANKUDINOV, A. L, et al. Parallel calculation of electron multiple scattering using Lanczos algorithms, Physical Review B. v.65, p.104107-104118, 2002. Disponível
em: ˂http://prb.aps.org> Acesso em: 10 Abr. 2011.
58 RAVEL, B. ATOMS: crystallography for the X-ray absorption spectroscopist. Journal of Synchrotron Radiation, v. 8, p.314-316, 2001. . Disponível em: ˂ http://journals.iucr.org/s/> Acesso em: 22 Jan. 2010.
59 GOMES, W. C.M, et al. An in situ X-ray absorption spectroscopy study of copper
nanoparticles in microemulsion. Colloids and Surfaces A: Physicochem. Eng. Aspects, v. 426, p. 18– 25, 2013. Disponível em: <http://www.sciencedirect.com> Acesso em: 18 Maio 2013.
60 HAAS, O; STRUIS, R.P.W.J; MCBREEN, J.M. Synchrotron X-ray absorption of LaCoO3 perovskite. Journal of Solid State Chemistry, v. 177, p.1000–1010, 2004. Disponível em: <http://www.sciencedirect.com> Acesso em: 18 Maio. 2012.
61 CROFT, M, et al. Systematic Mn d-configuration change in the La1-xCaxMnO3 system: A Mn
K-edge XAS study. Physical Review B, v. 55, p. 8726- 8732, 1997. Disponível em: ˂http://prb.aps.org> Acesso em: 10 Abr. 2011.
62 HAHN, J. E, et al. Observation of an electric quadrupole transition in the X- ray absorption spectrum of A Cu(II) complex. Chemical Physics Letters, v. 88, p.595- 598, 1982.
Disponível em: <http://www.sciencedirect.com> Acesso em: 8 Maio 2011.
63 CHEN, L. X, et al. Fe2O3 Nanoparticle Structures Investigated by X-ray Absorption Near- Edge Structure, Surface Modifications, and Model Calculations. The Journal of Physical Chemistry. B, v.106, p.8539-8546, 2002. Disponível em: ˂http://pubs.acs.org>, Acesso em: 20 Jan. 2010.
64 THORNTON, G; OWEN, I. W, DIAKUN, G. P. The two-band model of the LaCoO3 semiconductor-metal transition: a spectroscopic evaluation. Journal Physics.: Condens. Matter, v.3, p.417-422, 1991. Disponível em: ˂ http://iopscience.iop.org> Acesso em: 11 Jan. 2010.
65 RAVINDRAN, P, et al. Itinerant metamagnetism and possible spin transition in LaCoO3 by temperature/hole doping. Journal of Applied Physics, v.91, p. 291-303, 2002. Disponível em: ˂ http://scitation.aip.org/content/aip/journal/jap> Acesso em: 16Abr. 2010.
66 WOLD, A; WARD, R. Perowskite-Type Oxides of Cobalt, Chromium and Vanadium with Some Rare Earth Elements. Journal of the American Chemical Society. v.76, p.1029–1030, 1954.
67 HANSTEEN, O. H; FJELLVA°G, H; HAUBACKB , B. C. Crystal structure, thermal and magnetic properties of La4Co3O9. Phase relations for La4Co3O10−d (0.00_d_1.00) at 673 K. Journal of Materials Chemistry, v. 8, p. 2089–2093, 1998. Disponível em: ˂
http://pubs.rsc.org> Acesso em: 12 Abr. 2011.
68 MASTELARO,V. R; SOUZA, D. P. F; MESQUITA, R. A. X-ray absorption spectroscopic studies of Mn atoms in La1−xSrxMnO3+d compounds. X-ray Spectrometry, v. 31 p. 154–157,
2002.
69 SUBÍAS, G, et al. Local structure at the manganese site in mixed-valence manganites. Physical Review B, v.57, p. 748-754, 1998. Disponível em: ˂http://prb.aps.org> Acesso em: 20 Dez. 2011.
70 MELO, D. M. A, et al. XAFS characterization of La1_xSrxMnO3±d catalysts prepared by Pechinis method. Chemical Physics, v. 322 p.477–484, 2006. Disponível em:
<http://www.sciencedirect.com> Acesso em: 14 Maio 2010.
71 WANG, Y; FAN, H. J. Orbital ordering-driven ferromagnetism in LaCoO3 nanowires. Journal of Applied Physics, v. 108, p.053917-6, 2010. . Disponível em: ˂