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1. Engineering Transport in Manganites by Tuning Local Non-Stoichiometry in Grain Boundaries

Author

Chiabrera, F., Garbayo, I., Lopez-Conesa, L., Martin, G., Ruiz-Caridad, A., Walls, M., Ruiz-Gonzalez, L., Kordatos, A., Nunez, M., Morata, A., Estrade, S., Chroneos, A., Peiro, F., and Tarancon, A.

Subjects
Condensed Matter - Materials Science
Abstract

Interface-dominated materials such as nanocrystalline thin films have emerged as an enthralling class of materials able to engineer functional properties of transition metal oxides widely used in energy and information technologies. In particular, it has been proved that strain-induced defects in grain boundaries of manganites deeply impact their functional properties by boosting their oxygen mass transport while abating their electronic and magnetic order. In this work, the origin of these dramatic changes is correlated for the first time with strong modifications of the anionic and cationic composition in the vicinity of strained grain boundary regions. We are also able to alter the grain boundary composition by tuning the overall cationic content in the films, which represents a new and powerful tool, beyond the classical space charge layer effect, for engineering electronic and mass transport properties of metal oxide thin films useful for a collection of relevant solid state devices.

Published
2019
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2. Electron Tomography

Author

Torruella, P., Blanco-Portals, J., Yedra, Ll., López-Conesa, L., Rebled, J. M., Peiró, F., Estradé, S., Hull, Robert, Series Editor, Jagadish, Chennupati, Series Editor, Kawazoe, Yoshiyuki, Series Editor, Kruzic, Jamie, Series Editor, Osgood, Richard M., Series Editor, Parisi, Jürgen, Series Editor, Pohl, Udo W., Series Editor, Seong, Tae-Yeon, Series Editor, Uchida, Shin-ichi, Series Editor, Wang, Zhiming M., Series Editor, Peddis, Davide, editor, Laureti, Sara, editor, and Fiorani, Dino, editor

Published
2021
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4. Multiple strain-induced phase transitions in LaNiO3 thin films

Author

Weber, M. C., Guennou, M., Dix, N., Pesquera, D., Sánchez, F., Herranz, G., Fontcuberta, J., López-Conesa, L., Estradé, S., Peiró, F., Iñiguez, J., and Kreisel, J.

Subjects
Condensed Matter - Materials Science
Abstract

Strain effects on epitaxial thin films of LaNiO3 grown on different single crystalline substrates are studied by Raman scattering and first-principles simulation. New Raman modes, not present in bulk or fully-relaxed films, appear under both compressive and tensile strains, indicating symmetry reductions. Interestingly, the Raman spectra and the underlying crystal symmetry for tensile and compressively strained films are different. Extensive mapping of LaNiO3 phase stability is addressed by simulations, showing that a variety of crystalline phases are indeed stabilized under strain which may impact the electronic orbital hierarchy. The calculated Raman frequencies reproduce the principal features of the experimental spectra, supporting the validity of the multiple strain-driven structural transitions predicted by the simulations., Comment: 18 pages, 7 figures

Published
2016
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8. Electron Tomography

Author

Torruella, P., primary, Blanco-Portals, J., additional, Yedra, Ll., additional, López-Conesa, L., additional, Rebled, J. M., additional, Peiró, F., additional, and Estradé, S., additional

Published
2021
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9. Raman spectroscopy of wurtzite and zinc-blende GaAs nanowires: polarization dependence, selection rules and strain effects

Author

Zardo, I., Conesa-Boj, S., Peiro, F., Morante, J. R., Arbiol, J., Uccelli, E., Abstreiter, G., and Morral, A. Fontcuberta i

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Materials Science
Abstract

Polarization dependent Raman scattering experiments realized on single GaAs nanowires with different percentages of zinc-blende and wurtzite structure are presented. The selection rules for the special case of nanowires are found and discussed. In the case of zinc-blende, the transversal optical mode E1(TO) at 267 cm-1 exhibits the highest intensity when the incident and analyzed polarization are parallel to the nanowire axis. This is a consequence of the nanowire geometry and dielectric mismatch with the environment, and in quite good agreement with the Raman selection rules. We also find a consistent splitting of 1 cm-1 of the E1(TO). The transversal optical mode related to the wurtzite structure, E2H, is measured between 254 and 256 cm-1, depending on the wurtzite content. The azymutal dependence of E2H indicates that the mode is excited with the highest efficiency when the incident and analyzed polarization are perpendicular to the nanowire axis, in agreement with the selection rules. The presence of strain between wurtzite and zinc-blende is analyzed by the relative shift of the E1(TO) and E2H modes. Finally, the influence of the surface roughness in the intensity of the longitudinal optical mode on {110} facets is presented., Comment: 28 pages, 12 figures. to be published in Phys. Rev. B

Published
2009
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10. Structural and optical properties of high quality zinc-blende/wurtzite GaAs hetero-nanowires

Author

Spirkoska, D., Arbiol, J., Gustafsson, A., Conesa-Boj, S., Glas, F., Zardo, I., Heigoldt, M., Gass, M. H., Bleloch, A. L., Estrade, S., Kaniber, M., Rossler, J., Peiro, F., Morante, J. R., Samuelson, L., Abstreiter, G., and Morral, A. Fontcuberta i

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Materials Science
Abstract

The structural and optical properties of 3 different kinds of GaAs nanowires with 100% zinc-blende structure and with an average of 30% and 70% wurtzite are presented. A variety of shorter and longer segments of zinc-blende or wurtzite crystal phases are observed by transmission electron microscopy in the nanowires. Sharp photoluminescence lines are observed with emission energies tuned from 1.515 eV down to 1.43 eV when the percentage of wurtzite is increased. The downward shift of the emission peaks can be understood by carrier confinement at the interfaces, in quantum wells and in random short period superlattices existent in these nanowires, assuming a staggered band-offset between wurtzite and zinc-blende GaAs. The latter is confirmed also by time resolved measurements. The extremely local nature of these optical transitions is evidenced also by cathodoluminescence measurements. Raman spectroscopy on single wires shows different strain conditions, depending on the wurtzite content which affects also the band alignments. Finally, the occurrence of the two crystallographic phases is discussed in thermodynamic terms., Comment: 24 pages

Published
2009
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11. Strain-driven elastic and orbital-ordering effects on thickness-dependent properties of manganite thin films

Author

Infante, I. C., Sánchez, F., Fontcuberta, J., Wojcik, M., Jedryka, E., Estradé, S., Peiró, F., Arbiol, J., Laukhin, V., and Espinós, J. P.

Subjects
Condensed Matter - Materials Science
Abstract

We report on the structural and magnetic characterization of (110) and (001) La2/3Ca1/3MnO3 (LCMO) epitaxial thin films simultaneously grown on (110) and (001)SrTiO3 substrates, with thicknesses t varying between 8 nm and 150 nm. It is found that while the in-plane interplanar distances of the (001) films are strongly clamped to those of the substrate and the films remain strained up to well above t=100 nm, the (110) films relax much earlier. Accurate determination of the in-plane and out-of-plane interplanar distances has allowed concluding that in all cases the unit cell volume of the manganite reduces gradually when increasing thickness, approaching the bulk value. It is observed that the magnetic properties (Curie temperature and saturation magnetization) of the (110) films are significantly improved compared to those of (001) films. These observations, combined with 55Mn-nuclear magnetic resonance data and X-ray photoemission spectroscopy, signal that the depression of the magnetic properties of the more strained (001)LCMO films is not caused by an elastic deformation of the perovskite lattice but rather due to the electronic and chemical phase separation caused by the substrate-induced strain. On the contrary, the thickness dependence of the magnetic properties of the less strained (110)LCMO films are simply described by the elastic deformation of the manganite lattice. We will argue that the different behavior of (001) and (110)LCMO films is a consequence of the dissimilar electronic structure of these interfaces., Comment: 16 pages, 15 figures

Published
2007
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14. The effect of substrate on high-temperature annealing of GaN epilayers: Si versus sapphire

Author

González Díaz, Germán, Artús, L., Calleja, E., Cuscó, R., Iborra, E., Jiménez, J., Pastor, D., Peiró, F., González Díaz, Germán, Artús, L., Calleja, E., Cuscó, R., Iborra, E., Jiménez, J., Pastor, D., and Peiró, F.

Abstract

© American Institute of Physics. This work has been supported by the Spanish Ministry of Science and Technology under Contract Nos. MAT2004-0664 and MAT2004-02875. The authors wish to thank Dr. M. Marsal for her expert assistance with the EDX measurements., We have studied the effects of rapid thermal annealing at 1300 degrees C on GaN epilayers grown on AlN buffered Si(111) and on sapphire substrates. After annealing, the epilayers grown on Si display visible alterations with craterlike morphology scattered over the surface. The annealed GaN/Si layers were characterized by a range of experimental techniques: scanning electron microscopy, optical confocal imaging, energy dispersive x-ray microanalysis, Raman scattering, and cathodoluminescence. A substantial Si migration to the GaN epilayer was observed in the crater regions, where decomposition of GaN and formation of Si3N4 crystallites as well as metallic Ga droplets and Si nanocrystals have occurred. The average diameter of the Si nanocrystals was estimated from Raman scattering to be around 3 nm. Such annealing effects, which are not observed in GaN grown on sapphire, are a significant issue for applications of GaN grown on Si(111) substrates when subsequent high-temperature processing is required., Spanish Ministry of Science and Technology, Depto. de Estructura de la Materia, Física Térmica y Electrónica, Fac. de Ciencias Físicas, TRUE, pub

Published
2023

24. Silicon nanocrystals in carbide matrix

Author

Summonte, C., Allegrezza, M., Bellettato, M., Liscio, F., Canino, M., Desalvo, A., López-Vidrier, J., Hernández, S., López-Conesa, L., Estradé, S., Peiró, F., Garrido, B., Löper, P., Schnabel, M., Janz, S., Guerra, R., and Ossicini, S.

Published
2014
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39. Evolución de la morfología y facetaje de nanoestructuras de SnO2 crecidas por pirólisis en fase aerosol sobre sustratos de vidrio

Author

Morante, J. R., Cornet, A., Peiró, F., Arbiol, J., Rossinyol, E., Brinzari, V., Korotcenkov, G., and Golovanov, V.

Subjects
SnO2 thin films, HRTEM, spray pyrolysis, crystalline structure, semiconductor gas sensor, SnO2 capas finas, pirólisis en fase aerosol, estructura cristalina, sensor de gas semiconductor, Clay industries. Ceramics. Glass, TP785-869
Abstract

Nanostructural characteristics of polycrystalline SnO2 thin films determine their psychical and chemical properties as semiconductor gas sensor. Tin oxide thin films obtained by spray pyrolysis deposition on glass substrates have been studied (35nm - 300nm). We have studied the influence of the pyrolysis temperature (300ºC - 530ºC) on the crystallographic structure of the films. These samples have been characterised by X-ray diffraction, and high-resolution transmission electron microscopy. Some atomic models of growing have been proposed, with a double pyramidal structure and rhombic base.Las características nanoestructurales de las capas finas policristalinas de SnO2 determinan sus propiedades físicas y químicas como material sensor de gas. Se han analizado un conjunto de muestras (35nm - 300nm) crecidas por pirólisis en fase aerosol sobre substratos de vidrio, estudiando la influencia de la temperatura de pirólisis (375ºC - 530ºC) en la estructura cristalina de las capas. Estas muestras han sido caracterizadas mediante difracción de rayos X y microscopia electrónica de transmisión de alta resolución. Se han propuesto modelos atómicos de crecimiento, de estructura doble piramidal truncada y base rómbica, para las diferentes temperaturas de depósito.

Published
2004

49. ORDEREDGaN/InGaNNANORODS ARRAYS GROWN BY MOLECULAR BEAM EPITAXY FOR PHOSPHOR-FREE WHITE LIGHT EMISSION

Author

ALBERT, S., primary, BENGOECHEA-ENCABO, A., additional, SANCHEZ-GARCÍA, M.A., additional, BARBAGINI, F., additional, CALLEJA, E., additional, LUNA, E., additional, TRAMPERT, A., additional, JAHN, U., additional, LEFEBVRE, P., additional, LÓPEZ, L.L., additional, ESTRADÉ, S., additional, REBLED, J.M., additional, PEIRÓ, F., additional, NATAF, G., additional, DE MIERRY, P., additional, and ZUÑIGA-PÉREZ, J., additional

Published
2013
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50. Poster: Electronic Structure, Lattice Dynamics, and Transport

Author

Richter, Christoph, primary, Boschker, Hans, additional, Dietsche, Werner, additional, Mannhart, Jochen, additional, Brasse, M., additional, Jany, R., additional, Heyn, Ch., additional, Mannhart, J., additional, Wilde, M. A., additional, Grundler, D., additional, Tada, Masahiro, additional, Miyauchi, Yohei, additional, Yoshiya, Masato, additional, Yasuda, Hideyuki, additional, Sagarna, Leyre, additional, Maegli, Alexandra, additional, Yoon, Songhak, additional, Populoh, Sascha, additional, Shkabko, Andrey, additional, Weidenkaff, Anke, additional, Karthäuser, Silvia, additional, Manheller, Marcel, additional, Waser, Rainer, additional, Blech, Kerstin, additional, Simon, Ulrich, additional, Pengpan, T., additional, Boonthummo, A., additional, Togo, Atsushi, additional, Chaput, Laurent, additional, Tanaka, Isao, additional, Ramírez, M. A, additional, Simões, A. Z, additional, Longo, E., additional, Varela, J. A, additional, Xu, Pengxiang, additional, Schena, Timo, additional, Bihlmayer, Gustav, additional, Blügel, Stefan, additional, Thatribud, A., additional, Tungsurat, T., additional, Tan, X. L., additional, Chen, P. F., additional, Wang, L. F., additional, Zhi, B. W., additional, Wu, W. B., additional, Nikolaev, A. V., additional, Michel, K. H., additional, Tsvyashchenko, A. V., additional, Velichkov, A. I., additional, Salamatin, A. V., additional, Fomicheva, L. N., additional, Ryasny, G. K., additional, Sorokin, A. A., additional, Kochetov, O. I., additional, Budzynski, M., additional, Prieto, P., additional, Gómez, M. E., additional, Puig, T., additional, Obradors, X., additional, Palau, A., additional, Llordés, A., additional, Coll, M., additional, Vlad, R., additional, Gazquez, J., additional, Arbiol, J., additional, Guzmán, R., additional, Pomar, A., additional, Sandiumenge, F., additional, Ricart, S., additional, Rouco, V., additional, Ye, S., additional, Deutscher, G., additional, Chataigner, D., additional, Varela, M., additional, Magen, C., additional, Vanacken, J., additional, Gutierrez, J., additional, Moshchalkov, V. V., additional, Broglia, Giulia, additional, Montorsi, Monia, additional, Larcher, Luca, additional, Padovani, Andrea, additional, Nasr Esfahani, D., additional, Covaci, L., additional, Peeters, F. M., additional, Ohnishi, Hiromasa, additional, Kosugi, Taichi, additional, Miyake, Takashi, additional, Ishibashi, Shoji, additional, Terakura, Kiyoyuki, additional, Medarde, Marisa, additional, Straessle, Thierry, additional, Pomjakushin, Vladimir, additional, Martínez-Lope, María Jesus, additional, Alonso, José Antonio, additional, Nowak, R., additional, Chrobak, D., additional, Gerberich, W. W., additional, Niihara, K., additional, Wyrobek, T., additional, Estradé, S., additional, Rebled, J. M., additional, Walls, M. G., additional, de la Peña, F., additional, Colliex, C., additional, Córdoba, R., additional, Infante, I. C., additional, Herranz, G., additional, Sánchez, F., additional, Fontcuberta, J., additional, Peiró, F., additional, Velessiotis, D., additional, Douvas, A. M., additional, Dimitrakis, P., additional, Argitis, P., additional, Glezos, N., additional, Chrobak, Dariusz, additional, Gerberich, William W., additional, Nowak, Roman, additional, Meyer, Carola, additional, Spudat, C., additional, Müller, M., additional, Houben, L., additional, Maultzsch, J., additional, Goss, K., additional, Thomsen, C., additional, Schneider, C. M., additional, Reza Golobostanfard, Mohammad, additional, Abdizadeh, Hossein, additional, Schmidt, Manuel J., additional, Engels, Stephan, additional, Epping, Alexander, additional, Trellenkamp, Stefan, additional, Wichmann, Uwe, additional, Stampfer, Christoph, additional, Rocha, Paulo R. F., additional, Chen, Qian, additional, Kiazadeh, Asal, additional, Gomes, Henrique L., additional, Meskers, Stefan, additional, de Leeuw, Dago, additional, Paßens, Michael, additional, Busiakiewicz, Adam, additional, Franz, Adam W., additional, Barkschat, Christa S., additional, Urselmann, Dominik, additional, Müller, Thomas J. J., additional, Soltow, A., additional, Karthäuser, S., additional, Waser, R., additional, Zeng, Fei, additional, Yang, Jing, additional, Wang, Zhishun, additional, Lin, Yisong, additional, Li, Sizhao, additional, Hirschfeld, Julian A., additional, and Lustfeld, Hans, additional

Published
2013
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