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Controlling the elastic properties of materials is an issue that has been widely investigated because adapting available materials for incoming applications is required. Many efforts have been made in the last decade to make the elastic properties of ferroelectric materials adjustable for their use in high-technology products or processes. Additionally, in this new era of real-time wireless control, wireless devices are expected to replace traditional wired ones. However, there is no published research on visible-light wireless control of the elastic properties of ferroelectric materials. Here, we present the absolute proof the elasticity in polycrystalline BaTiO3 can be reversibly switched and linearly tuned with visible light. Thermal effects are definitively isolated so that the photo-induced phenomenon is unequivocally revealed. The light-induced change of Young’s modulus is originated by the increased screening of the charged domain walls under illumination. These results provide a promising avenue to the development of a new generation of optically driven devices based on elastically photosensitive ferroelectric materials., Postprint (author's final draft)

Optical means instead of electric fields may offer a new pathway for low-power and wireless control of magnetism, holding great potential to design next-generation memory and spintronic devices. Artificial multiferroic materials have shown remarkable suitability as platforms towards the optical control of magnetic properties. However, the practical use of magnetic modulation should be both stable and reversible and, particularly, it should occur at room temperature. Here we show an unprecedented reversible modulation of magnetism using low-intensity visible-light in Fe75Al25/BaTiO3 heterostructures, at room temperature. This is enabled by the existence of highly oriented charged domain walls arranged in arrays of alternating in-plane and out-of-plane ferroelectric domains with stripe morphology. Light actuation yields a net anisotropic stress caused by ferroelectric domain switching, which leads to a 90-degree reorientation of the magnetic easy axis. Significant changes in the coercivity and squareness ratio of the hysteresis loops can be light-modulated, encouraging the development of novel low energy-consumption wireless magneto-optical devices., Postprint (published version)

Conté els treballs dels estudiants de l'assignatura: T1. Present and Future of Gravitational Wave Astronomy. P. Blancafort, G. Dasca, A. da Rocha, G. Martín, J. Rodríguez, L. Solé. T2. Electrical signals and their physiological significance in plants. A. Creus, A. De Irizar, F. Illa, A. Quesada, N. Zaloznik. T3. Wireless and Powerless Sensor Systems. M. Ausejo, M. Ferré, E. Puy, A. Solà. T4. Modern applications of Ultrasound Imaging. L. Costa, A. Anglada, M. Bataller, G. Badia, D. Lecumberri, A. Cortés. T5. Sensors Systems for Space Applications. A. de Ribot, A. Navarro, M. Pliego, M. Raurich, M. Ruiz. T6. Sensor Technologies for Caring People with Parkinson’s disease. A. Gravenhorst, L. Cardell, M. Alcover, M. Llabrés. T7. Ús i calibratge d’activímetres en medicina nuclear. P. Feliu, I. Ibós, M. Jiménez, J. Llorente, H. López, O. Sales. T8. Control de qualitat d’un equip de tomografia per emissió de positrons (PET/CT). M. Artola, J. Bosch, C. López, E. Prat. T9. Instrumentació en Radiodiagnòstic. Utilització d’un equip d’adquisició d’imatges: Tomògraf CT. Qualitat de la imatge. J. Blanco, D. Boujbel, C. Buch, L. González, J. Salazar. T10. Instrumentación en Radiodiagnóstico. Utilización de un equipo de adquisición de imágenes: Tomógrafo TC. Calidad de los parámetros del haz de radiación. L. Benarroch, L. Novo, J. Kneisz, E. Prieto. T11. Radiation Oncology: Experimental Dosimetry Characterization. E. Alzuria, P. Benítez, J. Muñoz, R. Mora, P. Sabater, J. Vila, 2023/2024

Aims To evaluate if rivaroxaban, an oral factor Xa (FXa) inhibitor, could modify the expression in vitro of inflammatory and oxidative stress biomarkers in abdominal aortic aneurysmal (AAA) sites showing intraluminal thrombus. Methods AAA sites with intraluminal mural thrombus were obtained from six patients undergoing elective AAA repair. In addition, control abdominal aortic samples were obtained from six organ donors. AAA sites were incubated in the presence and absence of 50 nmol l–1 rivaroxaban. Results AAA sites showing thrombus demonstrated higher content of FXa than control. Interleukin-6 levels released from AAA [Control: median: 23.45 (interquartile range: 16.17–37.15) vs. AAA: median: 153.07 (interquartile range: 100.80–210.69) pg ml–1 mg tissue–1, P < 0.05] and the expression levels of nitric oxide synthase 2 were significantly higher in AAA than in control. The protein expression level of NADPH oxidase subunits gp67-and gp91-phox, but did not gp47-phox, were also significantly higher in the AAA sites than in control. Addition of rivaroxaban to AAA sites explants significantly reduced the release of interleukin-6 [median: 51.61 (interquartile range: 30.87–74.03) pg ml–1 mg tissue–1, P < 0.05 with respect to AAA alone] and the content of nitric oxide synthase 2, gp67 and gp91-phox NADPH subunits. The content of matrix metallopeptidase 9 was significantly higher in the AAA sites as compared to control. Rivaroxaban also reduced matrix metallopeptidase 9 content in AAA sites to similar levels to control. Conclusions FXa inhibition by rivaroxaban exerted anti-inflammatory and antioxidative stress properties in human AAA sites, suggesting a role of FXa in these mechanisms associated with the pathogenesis of AAA., Depto. de Salud Pública y Materno - Infantil, Fac. de Medicina, TRUE, pub

Low-consumption ceramics processing routes are expected to replace conventional ones due to environmental concerns. In this context, flash sintering is garnering interest because it allows dense ceramics to be obtained in just a few minutes and at relatively low temperatures. This is particularly interesting for sintering alkaline-based compounds due to the easy volatilization of these elements. In this work, current-controlled flash sintering is used to obtain potassium-sodium niobate (KNN)-based piezoceramics with refined microstructure and suitable stoichiometry, leading to improved functional properties. KNN-based materials are currently outstanding lead-free piezoceramics, with their properties highly sensitive to the proper construction of the polymorphic phase boundary, as in the case of the first promising composition (K0.44Na0.52Li0.04)(Nb0.86Ta0.10Sb0.04)O3. Results of this work show that sintering parameters may determine the polymorphic behavior of this system, thereby evincing flash sintering allows polymorphic phase boundary to be fine-tuned. It is demonstrated that the convergence of microstructure refinement and compositional control holds the potential for enhancing properties through a proper electric current control during flash sintering., Postprint (author's final draft)

The concept of multiphysics, where materials respond to diverse external stimuli, such as magnetic fields, electric fields, light irradiation, stress, heat, and chemical reactions, plays a fundamental role in the development of innovative devices. Nanomanufacturing, especially in low-dimensional systems, enhances the synergistic interactions taking place on the nanoscale. Light–matter interaction, rather than electric fields, holds great promise for achieving low-power, wireless control over magnetism, solving two major technological problems: the feasibility of electrical contacts at smaller scales and the undesired heating of the devices. Here, we shed light on the remarkable reversible modulation of magnetism using visible light in epitaxial Fe3O4/BaTiO3 heterostructure. This achievement is underpinned by the convergence of two distinct mechanisms. First, the magnetoelastic effect, triggered by ferroelectric domain switching, induces a proportional change in coercivity and remanence upon laser illumination. Second, light–matter interaction induces charged ferroelectric domain walls’ electrostatic decompensations, acting intimately on the magnetization of the epitaxial Fe3O4 film by magnetoelectric coupling. Crucially, our experimental results vividly illustrate the capability to manipulate magnetic properties using visible light. This concomitant mechanism provides a promising avenue for low-intensity visible-light manipulation of magnetism, offering potential applications in multiferroic devices., Postprint (published version)

Piezoelectric materials are widely used as functional element of electromechanical trans- ducers in a large number of domestic and industrial applications. Because of their low cost and relatively easy fabrication, piezoelectric transducers are mainly based on polycrys- talline ferroelectric oxides; that is, oxide-based ferroelectric ceramics. Although piezoelec- tric ceramics are extensively used, their fabrication entails two environmental issue. On the one hand, the most used piezoelectric materials contain toxic element, in particular a high lead content. On the other hand, the ceramic materials manufacture requires a high energy demand, since the heat treatments involve high temperatures, in general above 1200 ºC, for several hours. To solve these issues, new eco-friendly piezoelectric materials are required. In this context, this project focusses on obtained lead-free piezoceramics by a low cost fast sintering process. In particular, this project aims to obtain lead-free (K, Na)NbO3-based piezoceramics with tailored microstructure to show high electrome- chanical response. Flash sintering, a novel ultrafast sintering technique, will be used to obtain dense ceramics of (K, Na)NbO3 system. This sintering methodology leads to a higher control of the microstructure and, therefore, enhanced functional properties may be reached. Controlling the flash sintering parameters (i.e., applied electric field, electrical current density and dwelling time) is crucial for obtaining high-dense samples and, consequently, it has an influence in the microstructure and the functional properties, which is what this project studies. In this work, highly-dense KNL-NTS ceramics are obtained by current controled flash sintering. The results reveal a grain growth for a decreasing applied field and decreasing dwelling time, but the opposite for the current density. Moreover, regarding functional properties, the highest remnant polarization is obtained for the sample with the highest diele

Ba0.85Ca0.15Zr0.1Ti0.9O3 (BCZT) stands out among lead-free ferroelectric oxides under consideration to replace state-of-the-art high-sensitivity piezoelectric Pb(Zr,Ti)O3, for a range of energy conversion ceramic technologies. However, the best performances have been reported for very coarse-grained materials, and attempts to refine microstructure below 10 µm grain size consistently result in significant property degradation. Here a comprehensive study of the grain size effects on the properties of BCZT across the micron scale is reported, down to the verge of the submicron one. Results show a distinctive early evolution of properties for grain sizes between 1 and 5 µm. For the larger sizes in this range, an opposite effect is found for the piezoelectric charge coefficient and electric field-induced strain with respect to the very coarse-grained material, while very good overall performance is maintained. For the lower sizes, relaxor features appear, yet materials can still be poled indicating their ferroelectric nature. This strongly resembles size effects in the Pb(Mg1/3Nb2/3)O3-PbTiO3 system, driven by the slowing down of the relaxor to ferroelectric transition with size reduction, though kinetics seem to slow down across much larger grain sizes for BCZT. Concomitant changes in the polymorphic phase coexistence are described and discussed by synchrotron X-ray diffraction., Postprint (published version)

This paper presents two linearization strategies for a custom-designed wideband push-pull (PP) power amplifier (PA) for wired communication applications such as, for example, cable TV. Two digital predistortion (DPD) behavioral models are proposed to meet the in-band and out-of-band linearity requirements when efficiently amplifying wideband DOCSIS signals with high fractional bandwidth (FBW). A radiofrequency (RF) DPD linearizer based on a band-pass generalized memory polynomial (BP-GMP) behavioral model and a baseband (BB) I-Q DPD linearizer based on a harmonic distortion GMP (HD-GMP) behavioral model are proposed. Both DPD models take into account the harmonic distortion typical of high FBW amplification. Experimental results will show high efficient and linear amplification of a 4 × 192 MHz composite DOCSIS signal by properly combining a crest factor reduction (CFR) technique and the proposed DPD strategies., The work in this paper was funded by Huawei Technologies from March 2017 to April 2019; and supported in part by the project PID2020-113832RB- C21 funded by MCIN/AEI/10.13039/50110001103., Peer Reviewed, Postprint (author's final draft)

Conté els treballs dels estudiants de l'assignatura: T1. Sensors and Electronic Instrumentation in the Present and Future of Gravitational Wave Astronomy. D. Canyameres, M. Font, J. Ruiz, D. Zafra. T2. Electrical signals and their physiological significance in plants. D.Gil, O. Rovira, A. Samaniego, F. Serra, J. Vilaró. T3. Eye tracking technology and its applications. A. Acitores, J. Brieva, A. Doñate, F. Poca. T4. Non invasive ultrasound in humans. M. López, M. Massó, G. Morales, J. Navas, H. Sama. T5. Ús d’un activímetre per mesures de radiació. M. Llano, M. López, M. Montaña, L. Pedro-Botet, R. Prats. T6. Utilització d’un equip d’adquisició d’imatges: qualitat d’imatge d’un tomògraf PET A.Lopera, O. Parera, J. Pérez, A. Ramos, M. Tomàs, P. Villén. T7. Usage of a Tomographic Gammacamera for Image Acquisition. J. Amigó, D. Garcín, M. Isern, M. Maroto, S. Moll. T8. Instrumentació en Radiodiagnòstic. Utilització d’un equip d’adquisició d’imatges: Tomògraf TC. Qualitat dels paràmetres del feix de radiació G. Comas, S. Vives, L. García, A. Cortés, M. Burjalès. T9. Oncologia Radioteràpica. M. Escolà, J. González, M. Jiménez, P. Montero, A. Valenzuela., 2022/2023

Due to environmental concerns, extensive research has been carried out to develop high-performance lead-free piezoceramics capable of replacing commercial lead-based materials. The lead-free (Ba0.7Ca0.3)TiO3 -Ba(Zr0.2Ti0.8)O3 system has emerged as a candidate for room temperature transducer applications because a high piezoelectric charge coefficient is achieved in this system for compositions at the morphotropic phase boundary. However, conventional ceramic processing of these eco-friendly piezoceramics demands high energy consumption because long-lasting, high-temperature heat treatments are needed, which often lead to microstructural degradation that compromises the material reliability. Field-assisted flash sintering has started to be explored since the application of an adequate electric field was shown to significantly reduce the sintering time and temperature, thereby controlling grain growth. In this work, Ba0.85Ca0.15Zr0.1Ti0.9O3 ceramics are obtained by current-controlled flash sintering of mechanosynthesized nanopowders. Exhaustive control of the sintering parameters allows tailoring of the microstructure, which allows dense fine-grained flash-sintered ceramics exhibiting a high electric field-induced strain response to be obtained., This work was supported by the Agencia Estatal de Investigación (AEI), Spain, projects PGC2018-099158-B-I00 and PID2021–122708OB-C33. S. L-B. thanks Agència de Gestió d′Ajuts Universitaris i de Recerca (AGAUR), Catalonia, Spain, for the FI-SDUR contract (2020 FISDU 00489). The authors acknowledge the ESRF (The European Synchrotron) for provision of synchrotron radiation facilities, and we would like to thank the BM25 (SpLine) staff for assistance in using the beamline., Peer Reviewed, Postprint (published version)

© 2010 American Meteorological Society. This work has been partially supported by the MICINN (Spanish government) under Projects CGL2007-65891-C05-05/CLI (DB and JAG) and CGL2008-05939-C03-02/CLI (M. Anton). ERA-40 reanalysis data were provided by the ECMWF from their data server Web site (http://www.ecmwf.int/). MA thanks Junta de Extremadura-Consejeria de Infraestructuras y Desarrollo Tecnologico-and Fondo Social Europeo for concession of a postdoctoral grant. R. R. Garcia provided helpful comments on this manuscript. Two anonymous reviewers contributed to improving the final version of this paper., This paper analyzes the statistical relationship between the total ozone column (TOC) and atmospheric blocking using 40-yr European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-40) data for the 1978-98 period, with special emphasis on winter and the European and eastern Pacific sectors. Regional blocking occurrence is accompanied by a decrease of TOC within the anticyclonic circulation region and a distinctive ozone increase upstream and downstream (upstream and south) in the Pacific (European) sector. Blocking significantly enhances the likelihood of low TOC extremes, especially over the Scandinavian and the Alaska Peninsulas, where more than 50% of winter blocks lead to TOC values in the lowest tail of the distribution. The relationship between ozone miniholes and blocking is confined to the high latitudes of both basins and is strong in Europe, where about half of the ozone miniholes occur simultaneously with blocking. Blocking-related ozone miniholes (blocking ozone miniholes) are also among the most intense and persistent. Although blocking activity does not drive the interannual variability of regional ozone miniholes, blocking ozone miniholes account for up to two-thirds of the total observed trend of ozone miniholes in Europe. The polar vortex is proposed as a feasible candidate for explaining the enhanced coupling of blocking and ozone miniholes in Europe and its long-term modulation. Blocking ozone miniholes are consistent with an almost purely dynamic origin caused by horizontal transport of ozone-poor air and vertical motions working together at different levels to reduce ozone content. Although the contribution of the former is dominant, accounting for two-thirds of ozone reduction in the 330-850-K column, the effect of the latter becomes a distinctive feature of blocking ozone miniholes., MICINN (Spanish government), Junta de Extremadura-Consejería de Infraestructuras y Desarrollo Tecnológico, Fondo Social Europeo, Depto. de Física de la Tierra y Astrofísica, Fac. de Ciencias Físicas, TRUE, pub

Tesi en modalitat de cotutela: Universitat Politècnica de Catalunya i Universidade Federal de São Carlos, (English) Optical control of ferroelectric properties has been attracted a growing interest as an alternative to the conventional control by applied electric fields. However, the major drawback for achieving an effective reversible optical control of domain rearrangement in conventional ferroelectrics lies in their wide optical band gap. Recent researches has reported a new form to optically control of electric polarization and its related properties by using visible light. Specifically, a light-induced local movement of domain walls was achieved, whose effects shown that the photoresponse at both local and macroscopic scales is wavelength-independent. This new phenomenon of light-matter coupling has a non-negligible time response and no light power threshold was observed. Such characteristics are observed through the crystal lattice structure, photo-induced strain and dielectric permittivity. In addition, experimental evidences suggest that the light-activated phenomenon seems to be correlated with the existence of atypical ferroelectric interfaces, known as charged domain walls, whose principal signature is to host free and bound electric charge. Undoubtedly, this phenomenon offers new possibilities for technological applications that are as yet unexplored. This thesis focuses in overcome some questions that remains to be solved concerning to this light-activated phenomenon. That is: What is the physical insight about the photo-ferroelectric response? Is the extension towards polycrystalline materials feasible? Are there other physical properties different from those already controlled enable to be modified? To answer these question, the thesis divides into two parts: one theoretical and another one experimental. In the first part, a phenomenology model describing the visible light-induced photoresponse is developed, which assumes that visible light modifies charged domain wall compensation so that the built-in electric fields in the system changes, thereby trigge, (Español) El control óptico de las propiedades ferroeléctricas tiene un creciente interés como alternativa viable al control convencional mediante campos eléctricos. El mayor inconveniente para conseguir un control óptico efectivo y reversible de la configuración de dominios ferroeléctricos radica en que los ferroeléctricos convencionales tienen un alto gap de banda. Investigaciones recientes han reportado una nueva forma de controlar ópticamente la polarización eléctrica y sus propiedades relacionadas mediante el uso de luz visible. En particular, se ha conseguido lograr un movimiento local de las paredes del dominio inducido por la luz, cuyos efectos mostraron que la fotorrespuesta a escala local y macroscópica es independiente de la longitud de onda en el espectro visible. Este nuevo fenómeno de acoplamiento luz-materia tiene una respuesta temporal no despreciable y no se observó ningún umbral de potencia de luz. Tales características se han observado a través de la deformación fotoinducida y cambios en la permitividad dieléctrica con luz. Además, las evidencias experimentales sugieren que el fenómeno activado por la luz parece estar correlacionado con la existencia de interfaces ferroeléctricas atípicas, conocidas como paredes de dominios cargadas, cuya característica principal es albergar carga libre y ligada. Sin duda, este fenómeno ofrece nuevas posibilidades de aplicaciones tecnológicas aún inexploradas. Esta tesis se centra en superar algunas cuestiones que quedan por resolver en relación con este fenómeno activado por la luz. Esto es, ¿Cuál es el origen físico de la respuesta foto-ferroeléctrica? ¿Es factible la extensión de este fenómeno a materiales policristalinos? ¿Existen otras propiedades físicas distintas a las ya controladas que se puedan modificar con luz? Para responder a estas preguntas, la tesis se divide en dos partes: una teórica y otra experimental. En la primera parte, se desarrolla un modelo fenomenológico que describe la fotorrespuesta in, Postprint (published version)

Flash sintering is a novel sintering technique that allows high-density ceramics to be obtained at low temperatures and using short dwell times, thus providing an energy-efficient alternative to conventional sintering. The microstructure of flash-sintered samples can be fine-tuned by a proper control of electrical parameters such as current density, electric field, and current profile, yielding significant improvements of functional properties. The starting powder should also be carefully selected since better sintering results are reported for smaller green grain sizes. However, this work evidences time evolution of electrical properties of flash-sintered BaTiO3 ceramics from submicron powders. The results reveal that these transformations greatly depend on powder grain size and can be further adjusted with an adequate selection of electric power profiles. This work provides new insights into ongoing phenomena during field-assisted sintering, such as grain growth and defect formation dynamics. Although the results focus on BaTiO3, it offers a new pathway to tailor the microstructure of flash-sintered ceramics, which may be extended to other electronic materials., This work was supported by the Agencia Estatal de Investigación (AEI), Spain, project PGC2018-099158-B-I00. S. L-B. thanks Agència de Gestió dAjuts Universitaris i de Recerca (AGAUR), Catalonia, Spain, for the FI-SDUR contract (2020 FISDU 00489). The authors acknowledge the ESRF (The European Synchrotron) for provision of synchrotron radiation facilities, and we would like to thank the SpLine-BM25 staff for assistance in using the beamline., Peer Reviewed, Postprint (published version)

The demand to produce clean energy has been increasing over the last years due to the various climate changes, which are strongly afflicting the world. Therefore, it is necessary to implement new and alternative energy sources that contribute for the environment preservation. That is the case, for instance, of novel energy-storage devices, which could contribute for the current demand of clean energies. In fact, most of the system used nowadays are those lead-based materials, which are strongly pollutant and contribute for the environment contamination. In this way, the interest in the development and study of lead-free materials has become a real priority in the scientific community. The objective of the present work is to synthesize and investigate the physical properties of lead-free ferroelectric systems based on BaTiO3 (BT) with technological interest. In particular, the structural and dielectric properties have been investigated as a function of the Sn4+ content, used as a doping element in the BT hosting crystalline structure. The phase transition characteristics have been also analyzed in a wide temperature and frequency range., Postprint (author's final draft)

Photostrictive materials have a growing interest because of their great potential as light-driven actuators, among other optomechanical applications. In this context, the optical control of macroscopic strain in ferroelectrics has recently attracted remarkable attention as an effective alternative to the conventional electric control of strain. Here, a clear correlation between optical absorption and light-induced strain in polycrystalline BaTiO3 is shown. Specifically, the grain size and the sample thickness dependence of optical absorption when the material is irradiated with energy photons lower than the band gap evidence that light absorption at charged domain walls is the core of the observed photo-response in ferroelectrics. The photoinduced electronic reconstruction phenomenon is proposed as the primary physical mechanism for light absorption at charged domain walls. Results open a new pathway to designing ferroelectric-based devices with new functionalities like thickness gradient-based photo-controlled nanoactuators., Postprint (published version)