Person:
Marín Palacios, María Pilar

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First Name
María Pilar
Last Name
Marín Palacios
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Físicas
Department
Física de Materiales
Area
Física de la Materia Condensada
Identifiers
UCM identifierORCIDScopus Author IDWeb of Science ResearcherIDDialnet IDGoogle Scholar ID

Search Results

Now showing 1 - 10 of 22
  • Publication
    Stress and field contactless sensor based on the scattering of electromagnetic waves by a single ferromagnetic microwire
    (American Institute of Physics, 2014-09-01) Herrero Gómez, Carlos; Aragón Sánchez, Ana María; Hernando Rydings, Manuel; Marín Palacios, María Pilar
    In this paper, we report an experimental study on the microwave modulated scattering intensity for a single Fe_2.25Co_72.75Si_10B_15 amorphous metallic microwire. The modulation is driven by applying a bias magnetic field that tunes the magnetic permeability of the ferromagnetic microwire. Furthermore, by using a magnetostrictive microwire, we also demonstrate that the microwave scattering is sensitive to mechanical stresses. In fact, we present a wireless microwave controlled stress sensor, suitable for biological applications, as a possible use of this effect. In addition, a first order theoretical approximation accounts for the observed influence of the magnetic permeability on the scattering coefficients. That model leads to predictions in good agreement with the experimental results.
  • Publication
    A feasible pathway to stabilize monoclinic and tetragonal phase coexistence in barium titanate-based ceramics
    (Royal Soc. Chemistry, 2022-11) Necib, Jallouli; López Sánchez, Jesús; Rubio Marcos, Fernando; Serrano, Aída; Navarro Palma, Elena; Peña Moreno, Álvaro; Taoufik, Mnasri; Smari, Mourad; Rojas Hernández, Rocío Estefanía; Carmona Tejero, Noemí; Marín Palacios, María Pilar
    Multiphase coexistence has attracted significant interest in recent years because its control has entailed a significant breakthrough for the piezoelectric activity enhancement of lead-free piezoelectric oxides. However, the comprehension of phase coexistence still has many controversies including an adequate synthesis process and/or the role played by crystalline phases in functional properties. In this study, functional barium titanate [BaTiO_(3), (BTO)]-based materials with tunable functional properties were obtained by compositional modification via Bismuth (Bi) doping. Towards this aim, we systematically synthesized BTO-based materials by a sol-gel method, focusing on the control of Bi substitution in the BaTiO_(3) structure. In particular, we found that the substitution of Bi^(+3) leads to the stabilization of a monoclinic-tetragonal (M-T) phase boundary close to room temperature, which facilities the polarization process of the system. As a surprising result, we believe that the simple and cost-effective strategy and design principles described in this work open up the possibility of obtaining BTO-based lead-free ceramics with enhanced properties induced by the stabilization of the phase coexistence, expanding their application range.
  • Publication
    Self-assembly of iron oxide precursor micelles driven by magnetic stirring time in sol-gel coatings
    (Royal Society Chemical, 2019-06-09) López Sánchez, Jesús; Marín Palacios, María Pilar; Carmona Tejero, Noemí; Rodríguez de la Fuente, Óscar; Serrano, A.; Campo, A. del; Abuín, M.; Salas Colera, E.; Muñoz Noval, A:; Castro, G. R.
    The purpose of this work is to fabricate self-assembled microstructures by the sol-gel method and study the morphological, structural and compositional dependence of epsilon-Fe_2O_3 nanoparticles embedded in silica when glycerol (GLY) and cetyl-trimethylammonium bromide (CTAB) are added as steric agents simultaneously. The combined action of a polyalcohol and a surfactant significantly modifies the morphology of the sample giving rise to a different microstructure in each of the studied cases (1, 3 and 7 days of magnetic stirring time). This is due to the fact that the addition of these two compounds leads to a considerable increase in gelation time as GLY can interact with the alkoxide group on the surface of the iron oxide precursor micelle and/or be incorporated into the hydrophilic chains of CTAB. This last effect causes the iron oxide precursor micelles to be interconnected forming aggregates whose size and structure depend on the magnetic stirring time of the sol-gel synthetic route. In this paper, crystalline structure, composition, purity and morphology of the sol-gel coatings densified at 960 degrees C are examined. Emphasis is placed on the nominal percentage of the different iron oxides found in the samples and on the morphological and structural differences. This work implies the possibility of patterning epsilon-Fe_2O_3 nanoparticles in coatings and controlling their purity by an easy one-pot sol-gel method.
  • Publication
    Recursos didácticos de formación en el área de magnetismo y electromagnetismo para profesores y estudiantes de ESO y Bachillerato
    (2018-10-16) Presa Muñoz de Toro, Patricia de la; Marín Palacios, María Pilar; Hernando Grande, Antonio; Spottorno Giner, Jorge; Cobos Fernández, Miguel Ángel; Morales Casero, Irene; Archilla Sanz, Diego; Giacomone, Luis Fernando
    Este proyecto persigue un doble objetivo. Por un lado, por medio de acciones formativas específicas, facilitar al personal docente de secundaria y bachillerato los medios para el montaje y realización de experimentos sencillos de bajo coste, que no requieran un equipamiento especial para su ejecución, y que sirvan como introducción a la explicación de conceptos científicos, tales como campo magnético, inducción electromagnética, etc. Por otro, abrir el Instituto de Magnetismo Aplicado (IMA) de la Universidad Complutense de Madrid a la comunidad educativa en las modalidades ya desarrolladas en el IMA, como charlas, prácticas experimentales, prácticas de empresa, etc. y ofrecer la posibilidad de realizar en un entorno controlado diversos tipos de ensayos, experimentos y prácticas de laboratorio.
  • Publication
    Tuning metamaterials by using amorphous magnetic microwires
    (Nature publishing group, 2017-07-24) Lopez-Dominguez, V.; Garcia, M. A.; Marín Palacios, María Pilar; Hernando Grande, Antonio
    In this work, we demonstrate theoretically and experimentally the possibility of tuning the electromagnetic properties of metamaterials with magnetic fields by incorporating amorphous magnetic microwires. The large permeability of these wires at microwave frequencies allows tuning the resonance of the metamaterial by using magnetic fields of the order of tens of Oe. We describe here the physical basis of the interaction between a prototypical magnetic metamaterial with magnetic microwires and electromagnetic waves plus providing detailed calculations and experimental results for the case of an array of Split Ring Resonators with Co-based microwires.
  • Publication
    Effects of partial manganese substitution by cobalt on the physical properties of Pr_(0.7)Sr_(0.3)Mn_(1-x)Co_(x)O_(3) (0 = x=0.15) manganites
    (MDPI AG, 2023-02-13) Zdiri, Feriel; Alonso, José María; Mnasri, Taoufik; Presa Muñoz del Toro, Patricia de la; Morales, Irene; Martínez, José Luis; Ben Younes, Rached; Marín Palacios, María Pilar
    We have investigated the structural, magnetic, and electrical transport properties of Pr_(0.7)Sr_(0.3)Mn_(1-x)Co_(x) O_(3) nanopowders (x = 0, 0.05, 0.10 and 0.15). The Pechini Sol-gel method was used to synthesize these nanopowders. X-ray diffraction at room temperature shows that all the nano powders have an orthorhombic structure of Pnma space group crystallography. The average crystallite size of samples x = 0, 0.05, 0.10, and 0.15 are 33.78 nm, 29 nm, 33.61 nm, and 24.27 nm, respectively. Semi-quantitative chemical analysis by energy dispersive spectroscopy (EDS) confirms the expected stoichiometry of the sample. Magnetic measurements indicate that all samples show a ferromagnetic (FM) to paramagnetic (PM) transition with increasing temperature. The Curie temperature T-C gradually decreases (300 K, 270 K, 250 K, and 235 K for x = 0, 0.05, 0.10, and 0.15, respectively) with increasing Co concentrations. The M-H curves for all compounds reveal the PM behavior at 300 K, while the FM behavior characterizes the magnetic hysteresis at low temperature (5 K). The electrical resistivity measurements show that all compounds exhibit metallic behavior at low temperature (T < T rho) well fitted by the relation rho = rho_(0) + rho_(2)T^(2) + rho_(4.5) T^(4.5) and semiconductor behavior above T rho (T > T rho), for which the electronic transport can be explained by the variable range hopping model and the adiabatic small polaron hopping model. All samples have significant magnetoresistance (MR) values, even at room temperature. This presented research provides an innovative and practical approach to develop materials in several technological areas, such as ultra-high density magnetic recording and magneto resistive sensors.
  • Publication
    Scattering of microwaves by a passive array antenna based on amorphous ferromagnetic microwires for wireless sensors with biomedical applications
    (MDPI, 2019-07-12) Moya, Alberto; Archilla Sanz, Diego; Navarro Palma, Elena; Hernando Grande, Antonio; Marín Palacios, María Pilar
    Co-based amorphous microwires presenting the giant magnetoimpedance effect are proposed as sensing elements for high sensitivity biosensors. In this work we report an experimental method for contactless detection of stress, temperature, and liquid concentration with application in medical sensors using the giant magnetoimpedance effect on microwires in the GHz range. The method is based on the scattering of electromagnetic microwaves by FeCoSiB amorphous metallic microwires. A modulation of the scattering parameter is achieved by applying a magnetic bias field that tunes the magnetic permeability of the ferromagnetic microwires. We demonstrate that the OFF/ON switching of the bias activates or cancels the amorphous ferromagnetic microwires (AFMW) antenna behavior. We show the advantages of measuring the performing time dependent frequency sweeps. In this case, the AC-bias modulation of the scattering coefficient versus frequency may be clearly appreciated. Furthermore, this modulation is enhanced by using arrays of microwires with an increasing number of individual microwires according to the antenna radiation theory. Transmission spectra show significant changes in the range of 3 dB for a relatively weak magnetic field of 15 Oe. A demonstration of the possibilities of the method for biomedical applications is shown by means of wireless temperature detector from 0 to 100 degrees C.
  • Publication
    Gas diffusion electrodes on the electrosynthesis of controllable iron oxide nanoparticles
    (Nature Publishing Group, 2019-10-25) Prato, Rafael A; Van Vught, Vincent; Eggermont, Sam; Pozo, Guillermo; Marín Palacios, María Pilar; Fransaer, Jan; Dominguez-Benetton, Xochitl
    The electrosynthesis of iron oxide nanoparticles offers a green route, with significant energy and environmental advantages. Yet, this is mostly restricted by the oxygen solubility in the electrolyte. Gas-diffusion electrodes (GDEs) can be used to overcome that limitation, but so far they not been explored for nanoparticle synthesis. Here, we develop a fast, environmentally-friendly, room temperature electrosynthesis route for iron oxide nanocrystals, which we term gas-diffusion electrocrystallization (GDEx). A GDE is used to generate oxidants and hydroxide in-situ, enabling the oxidative synthesis of a single iron salt (e.g., FeCl_2) into nanoparticles. Oxygen is reduced to reactive oxygen species, triggering the controlled oxidation of Fe^(2+) to Fe^(3+), forming Fe_(3-x)O_(4-x) (0 <= x <= 1). The stoichiometry and lattice parameter of the resulting oxides can be controlled and predictively modelled, resulting in highly-defective, strain-heavy nanoparticles. The size of the nanocrystals can be tuned from 5 nm to 20 nm, with a large saturation magnetization range (23 to 73 A m^2 kg^(-1)), as well as minimal coercivity (similar to 1 kA m^(-1)). Using only air, NaCl, and FeCl_2, a biocompatible approach is achieved, besides a remarkable level of control over key parameters, with a view on minimizing the addition of chemicals for enhanced production and applications.
  • Publication
    “Ver, tocar, hacer”: una propuesta para acercar la ciencia a la sociedad
    (2021-04-14) Presa Muñoz de Toro, Patricia de la; Marín Palacios, María Pilar; Navarro Palma, Elena; López Sánchez, Jesús; Gálvez Alonso, Fernando; Giacomone, Luis Fernando; Morales Casero, Irene; Cobos Fernández, Miguel Ángel; Archilla Sanz, Diego; Gorgui Birame, Papa; Alshalawi, Dhoha; Diaz Luque, Omar
    Este proyecto persigue un doble objetivo. Por un lado, por medio de acciones formativas específicas, facilitar al personal docente de institutos de secundaria y bachillera los medios para el montaje y realización de experimentos sencillos de bajo coste, que no requieran un equipamiento especial para su ejecución, y que sirvan como introducción a la explicación de conceptos científicos que suelen ser complejos, tales como campo magnético, inducción electromagnética, etc. Por otro, abrir el laboratorio a la comunidad educativa en las modalidades ya desarrolladas en el Instituto de Magnetismo Aplicado (UCM), como charlas, prácticas experimentales, prácticas de empresa, etc. y ofrecer la posibilidad de realizar en un entorno controlado diversos tipos de ensayos, experimentos y prácticas de laboratorio. Dado el carácter eminentemente práctico y experimental de los contenidos de las acciones formativas, nos centraremos en el diseño de experimentos bajo la consigna “Do it yourself”, de modo que puedan ser fácilmente realizados por los estudiantes con un mínimo de requisitos técnicos. Este método de “ver, tocar, hacer” no sólo ayuda a internalizar conceptos teóricos, sino que sirve también como vehículo motivador de la práctica científica. Este tipo de actividad resulta más atractiva, cercana y eficaz a la hora de despertar vocaciones científicas desde edades tempranas
  • Publication
    Correction: A feasible pathway to stabilize monoclinic and tetragonal phase coexistence in barium titanate-based ceramics
    (Royal Soc. Chemistry) Necib, Jallouli; López Sánchez, Jesús; Rubio Marco, Fernando; Serrano, Aída; Navarro Palma, Elena; Peña Moreno, Álvaro; Mnasri, Taoufik; Smari, Mourad; Rojas Hernández, Rocío Estefanía; Carmona Tejero, Noemí; Marín Palacios, María Pilar