¿Existe un desajuste entre la percepción de calidad de los empleados y clientes?

Novenes Jornades de Foment de la Investigació de la FCHS (Any 2003-2004)La calidad de servicio se ha convertido en un tema de gran importancia para la dirección empresarial y distintos ámbitos de investigación, básicamente por su capacidad para generar ventaja competitiva y mantener o aumentar la cuota del mercado y favorecer la satisfacción de los empleados. La dificultad de definición del concepto de calidad y la necesidad de desarrollar instrumentos útiles para su gestión ha llevado al desarrollo de distintos modelos multidimensionales de calidad. Pero en general, puede afirmarse que el objetivo principal que se persigue con este interés por la calidad es “la satisfacción del cliente y la eficiencia en el logro de esa satisfacción, con el fin de mantener u aumentar la competitividad organizacional”. Algunos modelos han considerado la calidad desde la perspectiva de la organización, que estudian la calidad percibida por el proveedor del servicio (perspectiva del servicio ofrecido). También existen otros modelos, que estudian la calidad tal y como es percibida por el cliente (perspectiva del servicio recibido, OLSEN, 1996). Teniendo en cuenta estos modelos el objetivo de esta investigación es determinar si existe un desajuste entre la percepción de la calidad de servicio de los empleados y la de los clientes de los hoteles. La muestra esta formada por 25 empleados de contacto con el usuario y 60 clientes que han hecho utilizado las instalaciones del hotel, con al menos una noche de estancia. Los hoteles eran establecimientos urbanos de la provincia de Castellón, de tres y cuatro estrellas. Los ANOVAS realizados muestran que existen diferencias significativas en la percepción de la calidad del servicio intangible entre empleados y clientes. Estas diferencias se sitúan en garantía de calidad, capacidad de respuesta y autenticidad. En cuanto al resto de variables consideradas los análisis no indican la existencia de diferencias significativas a tener en cuenta

Role of pO2 and film microstructure on the memristive properties of La2NiO4+δ/LaNiO3−δ bilayers

Altres ajuts: ICN2 is funded by the CERCA programme/Generalitat de Catalunya.LaNiO/LaNiO bilayers deposited at varying pO conditions resulted in remarkable differences in film microstructure and cell parameters, directly affecting the electrical behaviour of Pt/LaNiO/LaNiO/Pt devices. The devices deposited at low pO showed the largest memristance. We propose this is due to the formation of a p-type Schottky contact between LaNiO and LaNiO, where the extent of its carrier depletion width can be modulated by the electric-field induced drift of interstitial oxygen ions acting as mobile acceptor dopants in LaNiO

Bipolar "table with legs" resistive switching in epitaxial perovskite heterostructures

We report the experimental investigation of bipolar resistive switching with "table with legs" shaped hysteresis switching loops in epitaxial perovskite GdBaCo O /LaNiO bilayers deposited by pulsed laser deposition. The possibility of varying the resistivity of GdBaCo O by changing its oxygen content allowed engineering this perovskite heterostructure with controlled interfaces creating two symmetric junctions. It has been proved that the resistance state of the device can be reproducibly varied by both continuous voltage sweeps and by electrical pulses. The symmetric devices show slightly non-symmetric resistance profiles, which can be explained by a valence change resistive switching model, and presented promising multilevel properties required for novel memories and neuromorphic computing

Isotope Exchange Raman Spectroscopy (IERS): a novel technique to probe physicochemical processes inin situsitu

We have developed a novel in situ methodology for the direct study of mass transport properties in oxides with spatial and unprecedented time resolution, based on Raman spectroscopy coupled to isothermal isotope exchanges. Changes in the isotope concentration, resulting in a Raman frequency shift, can be followed in real time, not accessible by conventional methods, enabling complementary insights for the study of ion transport properties of electrode and electrolyte materials for advanced solid-state electrochemical devices. The proof of concept and strengths of isotope exchange Raman spectroscopy (IERS) are demonstrated by studying the oxygen isotope back-exchange in gadolinium-doped ceria (CGO) thin films. Resulting oxygen self-diffusion and surface exchange coefficients are compared to conventional time-of-flight secondary ion mass spectrometry (ToF-SIMS) characterisation and literature values, showing good agreement, while at the same time providing additional insight, challenging established assumptions. IERS captivates through its rapidity, simple setup, non-destructive nature, cost effectiveness and versatile fields of application and thus can readily be integrated as new standard tool for in situ and operando characterization in many laboratories worldwide. The applicability of this method is expected to consolidate our understanding of elementary physicochemical processes and impact various emerging fields including solid oxide cells, battery research and beyond

Epitaxial Thin Films of Lanthanum Nickel Oxides: Deposition by PI-MOCVD, Structural Characterization and High Temperature Transport Properties

En los últimos años ha habido un interés creciente en el estudio de el compuesto La2NiO4+?, debido a sus propiedades como conductor mixto iónico-electrónico, que lo hacen adecuado para su utilización en dispositivos electroquímicos, tales como cátodo para pilas de combustible de óxido sólido a temperaturas intermedias (IT-SOFC), membranas de permeación o sensores de gas. La estructura de fase La2NiO4+? está formada por láminas de LaNiO3, de tipo perovskita, alternadas con láminas de LaO de tipo cloruro sódico, en las cuales puede incorporarse oxígeno sobreestequiométrico. Esta estructura laminar es la responsable de la anisotropía en las propiedades del La2NiO4+?, dando lugar a una conductividad iónica y electrónica que es entre dos y tres órdenes de magnitud superior a lo largo del plano ab, en comparación con la dirección del eje c.Este trabajo consiste en el estudio, desde un punto de vista fundamental, de películas delgadas epitaxiales de La2NiO4+? orientadas a lo largo del eje c y crecidas por la técnica de deposición química en fase vapor de precursores organometálicos por inyección pulsada (PI-MOCVD) sobre diferentes sustratos, con el fin de adquirir una mejor comprensión de sus características microestructurales, su variación con la tensión y la influencia de la tensión en las propiedades de transporte a elevada temperatura. Además, el crecimiento epitaxial permite la medida de las propiedades de las películas de La2NiO4+? en dos direcciones perpendiculares, obteniendo una medida directa de la anisotropía del material.El La2NiO4+? es el primer miembro (n = 1) de la familia Ruddlesden-Popper Lan+1NinO3n+1, en la que la estructura de cada miembro está formada por un número n de bloques perovskita LaNiO3 alternados entre bloques LaO tipo cloruro sódico. Asimismo se han intentado depositar películas orientadas a lo largo del eje c de los miembros n = 2, 3 e ?, y se ha estudiado la variación las propiedades de transporte a lo largo de la serie Lan+1NinO3n+1. En la tesis se realiza una introducción a los conductores mixtos iónicos-electrónicos (MIEC) y a los cátodos para pilas de combustible de óxido sólido (SOFC), como una posible aplicación del material La2NiO4+?. Se describen las propiedades más importantes de la fase La2NiO4+?, y de los miembros n =2, 3 e ? de la familia Lan+1NinO3n+1, así como el estado del arte de la preparación de películas delgadas de estos materiales.A continuación se describe la técnica de deposición química en fase vapor de precursores organometálicos por inyección pulsada (PI-MOCVD), acompañada de una descripción detallada de los parámetros de depósito seleccionados, y del equipo PI-MOCVD utilizado. También se describen las técnicas utilizadas en la caracterización de las películas delgadas de Lan+1NinO3n+1.Posteriormente se describen los parámetros de depósito optimizados para la deposición de películas epitaxiales de La2NiO4+? y se realiza una caracterización estructural, morfológica y microestructural en función del espesor de las películas, del sustrato utilizado y de la temperatura. También se detalla y describe la conductividad total de películas epitaxiales de diferente espesor medida. Para éstas películas se han medido, además, las propiedades de intercambio y de difusión de oxígeno utilizando dos técnicas diferentes: la técnica de intercambio de isótopos y la técnica de relajación de la conductividad. Los resultados de estas medidas se discuten en función de la microestructura de las películas. Por último, se ha completado el estudio describiendo los primeros resultados de deposición de otros miembros de la familia Ruddlesden-Popper. La evolución de las propiedades de transporte total de las películas delgadas de Lan+1NinO3n+1 se han relacionado con el número de láminas tipo perovskita n.In the last years there has been a great interest in the study of the La2NiO4+? compound due to its mixed ionic-electronic properties, which make it suitable in electrochemical devices, such as cathode in Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFC), permeation membranes or gas sensors. The La2NiO4+? phase structure is formed by perovskite-type LaNiO3 layers alternated with rocksalt-type LaO layers, in which hyperstoichiometric oxygen can be incorporated. This layered structure is responsible for the anisotropy in the La2NiO4+? properties, leading to electronic and ionic conductivity three orders of magnitude higher along the ab plane, in comparison with the c-axis direction.This work is focused on the study, from a fundamental point of view, of epitaxial c-axis oriented La2NiO4+? thin films deposited by PI-MOCVD technique on different substrates, in order to achieve a better comprehension of the microstructural characteristics, their variation with strain and their influence in its high temperature transport properties. Moreover, the epitaxial growth of the films permits the measurement of the properties of the La2NiO4+? in two perpendicular directions, to have a direct inset of the anisotropy.The La2NiO4+? phase is the n = 1 member of the Lan+1NinO3n+1 Ruddlesden-Popper family, in which the structure of each member is formed by a n number of perovskite layers alternated between rock-salt layers. We have also attempted to deposit c-axis oriented films of the n = 2, n = 3 and n = 1 members and studied the variation of the transport properties through the different members of the family.First, Chapter 1 consists of an introduction to the mixed ionic-electronic conductors (MIEC) and to the solid oxide fuel cell (SOFC) cathodes, as a possible application of the La2NiO4+? material. The most remarkable properties of the La2NiO4+? phase, and of the n = 2, 3 and 1 members of the Lan+1NinO3n+1 family are analyzed, as well as the state of the art in the preparation of thin films of these materials.In Chapter 2, the Metalorganic Chemical Vapor Deposition (MOCVD) technique is described, accompanied by a detailed description of the selected experimental deposition parameters and of the Pulsed Injection MOCVD equipment used. Chapter 3 summarizes all the techniques used for the Lan+1NinO3n+1 thin film characterization.In Chapter 4, the optimized experimental parameters for the deposition of epitaxial La2NiO4+? thin films are described. Structural, morphological and microstructural characterization is performed as a function of film thickness, substrate used and temperature. Total conductivity of epitaxial layers is also described and discussed. In Chapter 5 we have studied the oxygen exchange and transport of the La2NiO4+? thin films by two different techniques: the oxygen isotope exchange and the electrical conductivity relaxation. Results are discussed as a function of microstructure.Finally, in Chapter 6, the study is completed describing the first results of the deposition of the other members of the Ruddlesden-Popper family. Evolution of the total conductivity properties of the Lan+1NinO3n+1 films has been related to the n number of perovskite layers

Deposition and characterisation of epitaxial oxide thin films for SOFCs

22 páginas, 13 figuras.This paper reviews the recent advances in the use of thin films, mostly epitaxial, for fundamental studies of materials for solid oxide fuel cell (SOFC) applications. These studies include the influence of film microstructure, crystal orientation and strain in oxide ionic conducting materials used as electrolytes, such as fluorites, and in mixed ionic and electronic conducting materials used as electrodes, typically oxides with perovskite or perovskite-related layered structures. The recent effort towards the enhancement of the electrochemical performance of SOFC materials through the deposition of artificial film heterostructures is also presented. These thin films have been engineered at a nanoscale level, such as the case of epitaxial multilayers or nanocomposite cermet materials. The recent progress in the implementation of thin films in SOFC devices is also reported.The authors would like to acknowledge the Spanish Ministry of Education for funding through different projects (MAT2008-03501, Consolider-Ingenio CSD2008-024).Peer reviewe

BSCF epitaxial thin films: Electrical transport and oxygen surface exchange

7 páginas, 10 figuras, 1 tabla.-- et al.Ba0.5Sr0.5Co0.8Fe0.2O3−δ (BSCF) shows promising oxygen transport properties for the use as oxygen separation membranes and cathode material for solid oxide fuel cells. In order to evaluate the electrical conductivity properties as well as surface exchange coefficients without the influence of grain boundaries present in polycrystalline bulk samples, high-quality epitaxial BSCF thin films on single crystal NdGaO3 (110) (NGO) substrates were prepared for the first time. This was achieved by pulsed laser deposition (PLD) using single-phase cubic targets sintered from powder prepared via the mixed oxide route. Structural and compositional properties of the thin films were verified by various X-ray diffraction techniques as well as by scanning electron microscopy (SEM). The electrical conductivity of the thin films was measured in dependence of temperature and compared to values obtained by measurements on polycrystalline bulk samples from the same powder as well as data from literature, showing different activation energies and higher general conductivity. Dependence of the conductivity on oxygen partial pressure has also been studied, revealing a rather small variation and indicating a possible phase change beginning to occur at oxygen partial pressures below 10−4 bar. Additionally, the surface exchange coefficient kChem of the purely surface exchange controlled samples was determined by a conductivity relaxation technique and yielded an activation energy of 93 kJ/mol.Financial support fromthe Helmholtz Association of German Research Centres (Initiative and Networking Fund) through the MEM-BRAIN Helmholtz Alliance is gratefully acknowledged. The authors also thank the DFG-Research Center for Functional Nanostructures (CFN, project F2.1) for support.Peer reviewe

Defects in layered-structure mixed ionic-electronic GdBaCo2O5.5 and La2NiO4 epitaxial films and their role in charge transport

Trabajo presentado a la Conferencia "BNC-b Research Meeting" celebrada en Barcelona el 14 de julio de 2011.-- et al.We thank the Spanish science and tech ministry: (MAT2008-04931, CONSOLIDER-CSD2008-023), JAE-PreDoc.Peer reviewe

La 4 Ni 3 O 10−δ as an efficient solid oxide fuel cell cathode: electrochemical properties versus microstructure

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Anisotropic 18O tracer diffusion in epitaxial films of GdBaCo2O5+δ cathode material with different orientations

The layered structure of the orthorhombic GdBaCo2O 5+δ (GBCO) double perovskite compound, currently considered as a promising cathode material in Solid Oxide Fuel Cells (SOFCs), is believed to induce a high degree of anisotropy in the oxygen diffusion coefficient, being maximum along the a-b plane in comparison to the diffusion along the c-axis direction. In this study we have deposited films with different orientation: pure c-axis and a-axis orientation on SrTiO3(001) and NdGaO 3(110) single crystals, respectively. The oxygen diffusion was analysed by isotopic 18O exchange depth profiling (IEDP) and Time-of-flight Secondary Ion Mass Spectrometry (ToF-SIMS) in the films along the longitudinal and transverse directions at different exchange temperatures and exposure times. The magnitude of longitudinal D* at low temperatures shows a clear anisotropy. The oxygen diffusion along the a-axis shows comparable values to the bulk polycrystalline GBCO, while it is about one order of magnitude lower along the c-axis of the structure. The corresponding oxygen surface exchange rates k* do not show any anisotropy having comparable values for c-axis and a-axis orientation. These k* values are slightly larger than those reported for bulk material showing that thin film textured cathodes may have enhanced activity for oxygen reduction at low temperatures. This journal is © The Royal Society of Chemistry 2013.The authors would like to acknowledge the Spanish Ministry of Education and Culture for financial support (MAT2011-29081-C02-01 and CONSOLIDER-INGENIO CSD2008-0023 projects). This research was also supported by a Marie Curie Intra European Fellowship within the seventh European Community Framework Programme (PIEF-GA-2009-252711) (for M.B). J. Z. thanks the Spanish National Research Council (CSIC) for the JAE-PreDoc Scholarship.Peer Reviewe