J. M. Barandiarán

Universidad del País Vasco / Euskal Herriko Unibertsitatea, Leioa, Basque Country, Spain

Are you J. M. Barandiarán?

Claim your profile

Publications (457)808.77 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Abstract A significant enhancement in coercivity was achieved by grain boundary modification through low temperature infiltration of Pr75(Cu0.25Co0.75)25 eutectic alloy in rare-earth lean (Pr/Nd)–Fe–B/α-Fe nanocomposite magnets. The infiltration procedure was carried out on ribbons and hot-deformed magnets at 600–650 °C for different time durations. In Nd2Fe14B/α-Fe ribbons, the coercivity increased from 5.3 to 23.8 kOe on infiltration for 4 h. The Pr2Fe14B/α-Fe hot-deformed magnet shows an increase in coercivity from 5.4 to 22 kOe on infiltration for 6 h. The increase in the coercivity comes at the expense of remnant magnetization. X-ray diffraction studies confirm the presence of both the hard Nd2Fe14B and soft α-Fe phases. A decrease in the soft α-Fe phase content was observed after infiltration.
    Full-text · Article · Jul 2016 · Journal of Magnetism and Magnetic Materials
  • [Show abstract] [Hide abstract]
    ABSTRACT: Polymer-based magnetoelectric materials show increasing interest for a large number of applications and, in particular, for the development of magnetic sensors. Nevertheless, relevant parameters such as sensitivity, accuracy, linearity, hysteresis and resolution have been vaguely or never discussed. This work reports on those parameters on a Metglas/poly(vinylidene fluoride)/Metglas magnetoelectric laminate.The sensitivity and resolution determined for the DC (30 mV·Oe-1 and 8 μOe) and AC magnetic field sensor (992 mV·Oe-1 and 0.3 μOe) are favorably comparable with the most sensitive polymer-based ME sensors. Further, the correlation coefficient, linearity and accuracy values are 0.995, 95.9% and 99.4% for the DC magnetic field sensor and 0.9998, 99.4% and 99.2% for the AC magnetic field sensor. Therefore, the magnetoelectric materials reported in the present study can be used for innovative AC/DC magnetic field sensors.
    No preview · Article · Feb 2016
  • Source

    Full-text · Presentation · Jan 2016
  • Source
    Victor A. L'vov · Anna Kosogor · Jose M. Barandiaran · Volodymyr A. Chernenko
    [Show abstract] [Hide abstract]
    ABSTRACT: A simple thermodynamic theory is proposed for the quantitative description of giant magnetocaloric effect observed in metamagneticshape memoryalloys. Both the conventional magnetocaloric effect at the Curie temperature and the inverse magnetocaloric effect at the transition from the ferromagnetic austenite to a weakly magnetic martensite are considered. These effects are evaluated from the Landau-type free energy expression involving exchange interactions in a system of a two magnetic sublattices. The findings of the thermodynamic theory agree with first-principles calculations and experimental results from Ni-Mn-In-Co and Ni-Mn-Sn alloys, respectively.
    Full-text · Article · Jan 2016 · Journal of Applied Physics
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Martensitic structures, transformation behavior and some magnetic properties of a new series of Mn49Ni42-xFexSn9 (x = 0 – 4 at.%) metamagnetic shape memory alloys have been studied as a function of Fe content and magnetic field. Fe doping decreased sharply the martensitic transformation temperatures. The XRD patterns showed different phases including orthorhombic structure, the L21 cubic phase and the fcc γ-phase at room temperature depending on Fe content. The magnetization curves, M-H, exhibited obvious metamagnetic transitions.
    Full-text · Article · Dec 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Magnetic Shape Memory Alloys have attracted a large interest from the basic aspects of their structural and magnetic transitions, as well as from their possible technological applications as very rapid, contactless, high stroke actuators. The typical alloy composition for such materials is Ni-Mn-X (X= Ga, In, Sb, Sn, etc.). The electronic and magnetic structure of such alloys are on the base of the displayed properties and are object of intense study by all kind of advanced experimental and theoretical methods. Here we present a summary of recent diffraction experiments with neutron, X ray Magnetic Circular Dichroism (XMCD) and X ray Photoemission Spectroscopy (XPS) that are complementary to elucidate the electronic and magnetic character of these alloys and the changes occurring at the martensitic transformation. While rigid band models can account for most electronic features, magnetism is better described by a localized moment mainly concentrated at the Mn atoms.
    Full-text · Article · Nov 2015 · Journal of Physics Conference Series
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The detection limit of thin film giant magneto-impedance (GMI) magnetic sensors has been investigated by measuring their magnetic noise. The GMI sensing elements are multilayers based on Fe20Ni80 Permalloy (Py), deposited by sputtering and patterned by photolithography in the form of 2-mm long and 50- to 130- $mu text{m}$ wide stripes. The multilayered samples had the following structure: [Py(170 nm)/Ti(6 nm)]3/Cu(250 nm)/[Ti(6 nm)/Py(170 nm)]3. As electronic conditioning circuits, different configurations of oscillators and detectors were tested in order to determine their influence on the total output voltage sensor noise. The latter was measured using a dynamic signal analyzer and the equivalent magnetic noise of the sensor was determined through the measured Fourier transfer function of the device at the operating point. Filtering and impedance matching strategies were implemented to minimize the equivalent magnetic sensor noise. Presently, a white noise level of 120 pT/ $surd $ Hz at 2 kHz is obtained.
    Full-text · Article · Nov 2015 · IEEE Sensors Journal
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: An influence of internal stress created by the crystal defects on the magnetically induced reorientation (MIR) of martensite variants in the ferromagnetic shape memory alloy (FSMA) has been analyzed. Using the internal stress conception, a noticeable influence of the spatial reconfiguration of crystal defects on the ordinary magnetostriction of FSMA and magnetic shape memory (MSM) effect has been predicted. It has been shown that the defect reconfiguration, which stabilizes the martensitic phase during martensite aging, increases the shear elastic modulus. The increase of shear modulus reduces the magnetostriction value and in this way suppresses the MSM effect. The magneto-thermo-mechanical training of aged alloys destabilizes the martensitic phase, restores the initial magnetostriction value, and promotes the MSM effect.
    Full-text · Article · Oct 2015 · Journal of Physics D Applied Physics
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Composite films with filler microparticles of Barium ferrite BaFe12O19 (BaFO, 1-20 wt.%) dispersed within P(VDF-TrFE) acting as piezoelectric polymeric matrix have been prepared by solvent evaporation. SEM and TEM images in combination with magnetic measurements clearly probe the good dispersion and random distribution of the BaFO microparticles within the films. Young’s modulus of the fabricated composites remains almost unchanged for all filler contents, indicating that this acts as a small defect within the P(VDF-TrFE) matrix. On the contrary, dielectric properties clearly reduce for low filler contents, 1 and 5 wt.%, and recover and increase their values in a smooth and monotonous way for higher BaFO filler contents of 10 and 20 wt.%. This trend is not followed by the electrical conductivity. Additionally, we have extended the study to fibers composed of BaFe12O19 microparticles within a PVDF matrix. Due to the big size of BaFO particles (about 1 μm in diameter), a proper fabrication of the fiber shaped composites has not been achieved. We found that true BaFO content are always lower than nominal ones. Results are discussed in terms of the influence of size and morphology of the BaFO particles on the initial properties of the pure polymeric matrix.
    Full-text · Article · Aug 2015 · European Polymer Journal
  • [Show abstract] [Hide abstract]
    ABSTRACT: We have developed a novel synthetic route for the preparation of single phase NdxBi1−xFe0.95Sc0.05O3 (NBFSO) nanopowder materials by a surfactant-assisted combustion-derived method. Rietveld fitting of the Powder X-ray diffraction data showed the nanopowder structure evolves from a distorted rhombohedral BiFeO3 crystalline structure (R3c, x = 0) to a orthorhombic structure (Pbnm, x = 0.10). Differential thermal analysis and thermogravimetric analysis (DTA/TGA) showed a crystallization temperature of 200 °C. Transmission electron microscopy (TEM) images revealed the presence of clusters formed by fine nanoparticles less than 60 nm in diameter. From Raman spectroscopy, the change from rhombohedral structure to cubic structure was observed by a drastic intensity reduction of the A1−2 and A1−3 Raman modes, with the A1−1 and A1−2 modes gradually merging together, indicating the merge of the orthorhombic phase. Despite the antiferromagnetic nature of bulk BiFeO3, the NBFSO nanopowders obtained displayed a ferromagnetic hysteresis loop, with coercivities of 0.08 T and remanent magnetizations of 0.65–4.05 Am2/kg when measured at room temperature. The increasing and uncompensated spins at the surface of nanoparticles and the canted internal spin by the tilt of FeO6 octahedral units and the structure transition appear to be the main reason for observed this ferromagnetic behavior.
    No preview · Article · Jul 2015 · Journal of Alloys and Compounds
  • [Show abstract] [Hide abstract]
    ABSTRACT: Companies and researchers involved in developing miniaturized electronic devices face the basic problem of the needed batteries size, finite life of time and environmental pollution caused by their final deposition. The current trends to overcome this situation point towards Energy Harvesting technology. These harvesters (or scavengers) store the energy from sources present in the ambient (as wind, solar, electromagnetic, etc) and are costless for us.
    No preview · Article · Jul 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In the last years the fabrication of multifunctional composite materials like the mixture of piezoelectric polymers with magnetic/magnetostrictive nanoparticles to give as result magnetoelectric (ME) composites has received great effort [1]. P(VDF-TrFE), in the poled ferroelectric phase, exhibits one of the highest piezoelectric responses among polymer materials over a wide range of temperature depending on its composition. Among ferrites, the ferrimagnetic material barium ferrite (BaFe12O19) shows particular magnetic properties as high coercive force and hysteresis losses. Despite its very low magnetostriction (9 ppm), Barium ferrite has very high magnetocrystalline anisotropy in the low-symmetry hexagonal magnetoplumbite crystal structure with hexagonal unit cell. Although barium ferrite particles have the shape of thin hexagonal platelets, the easy direction of magnetization remains along the c axis, which is perpendicular to the plates.
    Full-text · Article · Jul 2015 · IEEE Transactions on Magnetics
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Thin film-based Magneto-Impedance (MI) structures are well suited for developing highly sensitive magnetic microsensors, which can be directly integrated into microelectronic circuits. Permalloy (Py) based structures benefit from well-established preparation procedures and enhanced structural stability over amorphous based sensors. In this work we use Finite Element Method calculations to complement our previous studies on high permeability Py multilayers, in order to determine the combination of magnetic and non-magnetic layers that maximizes the MI performance in sandwiched structures. The results indicate that optimum behavior is expected when the thickness of the non-magnetic layer equals the magnetic ones. The study is performed with an open flux configuration (Py not enclosing the central non-magnetic conductor), which permits the fabrication of the complete stack of layers in a single deposition process. On the outcome of that analysis, samples with a sandwiched multilayer structure defined as [Py(100 nm)/Ti(6 nm)]4/Cu(400 nm)/[Ti(6 nm)/Py(100 nm)]4 have been prepared by magnetron sputtering and photolithography, having different dimensions. They were magnetically characterized by magneto-optical Kerr effect, displaying a well-defined transversal anisotropy, and the MI was measured in a network analyzer using a microstrip test-fixture. The measured MI ratio, defined as (Z-Zmin)/Zmin×100, reaches extraordinary values of 350%, while the sensitivity, calculated as the field derivative of the MI ratio, goes up to 300%/Oe (27 kΩ/T in absolute units). The MI ratio is lower than the best reported previously for amorphous CoSiB/Ag/CoSiB thin-film samples with closed-flux structure, but the sensitivity, which is the key parameter for the performance of sensors, is six times larger. These figures can be compared favorably with the ones obtained in wire-based samples, and definitely opens the way to incorporate thin-film structures in low-field MI magnetic sensors.
    Full-text · Article · Jul 2015 · Journal of Magnetism and Magnetic Materials
  • Source

    Full-text · Article · Jul 2015 · Solid State Phenomena

  • No preview · Conference Paper · Jul 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Magnetoelectric response at the radio frequency range has been studied as a function of temperature. For that purpose, we have fabricated sandwich-type laminated composites in which the Fe61.6Co16.4Si10.8B11.2 alloy was used as the magnetostrictive element and polyvinylidene fluoride (PVDF) as the piezoelectric one. The Fe61.6Co16.4Si10.8B11.2 amorphous ribbon shows good magnetic properties, with a magnetostriction close to 30 ppm and a piezomagnetic coefficient in as-quenched state and for a long ribbon of ${21.4 times 10^{-3}}$ ppm/Am $^{{ -1}}$ . Even though PVDF shows a higher piezoelectric coefficient ( ${d} _{{33}}={{15}}$ pC/N) than the high temperature poly and copolymides, the advantage of using these poly- and copolymides is the great stability shown at temperatures close to 200 °C. Considering this, the influence of temperature in laminated composites and in their components (epoxy, piezoelectric, and magnetostrictive constituents) has been measured and discussed.
    Full-text · Article · Jul 2015 · IEEE Transactions on Magnetics
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A flexible, low-cost energy-harvesting device based on the magnetoelectric (ME) effect was designed using Fe64Co17Si7B12 as amorphous magnetostrictive ribbons and polyvinylidene fluoride (PVDF) as the piezoelectric element. A 3 cm-long sandwich-type laminated composite was fabricated by gluing the ribbons to the PVDF with an epoxy resin. A voltage multiplier circuit was designed to produce enough voltage to charge a battery. The power output and power density obtained were 6.4 μW and 1.5 mW cm−3, respectively, at optimum load resistance and measured at the magnetomechanical resonance of the laminate. The effect of the length of the ME laminate on power output was also studied: the power output exhibited decays proportionally with the length of the ME laminate. Nevertheless, good performance was obtained for a 0.5 cm-long device working at 337 KHz within the low radio frequency (LRF) range.
    Full-text · Article · Jun 2015 · Smart Materials and Structures
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We report two possible routes of fabrication of large surfaces of ferromagnetic shape memory antidots with tunable pore size and center-to-center distances. By using the drop coating method, we have prepared a large area of 2D arrays (typically 1cm2) of polystyrene spheres (PS) (1.4±0.1μ m diameter) on a Si substrate. We have used reactive ion etching with a gas mixture of O2 (12sccm) and Ar (5sccm) to reduce the diameter of the PS spheres whereby controlling the size of pores. The film deposition was performed on a substrate heated at 500°C (route 1) and at room temperature with subsequent annealing in a furnace at 500°C for 4 hours (route 2). Route 1 proved to be promising but more work is needed to optimize it. The antidots of Ni-Mn-Ga obtained along route 2 are ferromagnetic with a Curie temperature ~100°C, and a spread martensitic transformation (between -100°C and -30°C).
    Full-text · Article · May 2015 · Key Engineering Materials
  • P. Lázpita · J. Escolar · V.A. Chernenko · J.M. Barandiarán
    [Show abstract] [Hide abstract]
    ABSTRACT: Two different metamagnetic shape memory alloys of nominal composition Ni50Mn36In14 and Ni42Co8Mn39Sn11 have been studied by means of modified Arrott plots to give insight into the magnetic states of both the austenitic and martensitic phases. For Ni50Mn36In14 alloy, the same critical exponents (β = 0.32 and γ = 2.0) are obtained in austenite and martensite. They suggest that localized moments at Mn atoms are responsible for the magnetism of both phases according to the Ising model. The martensite, however, displays a rather complex behavior because β continuously changes with temperature. In Ni43Co6.5Mn39Sn11.5, critical exponents in the austenite are β = 0.27 and γ = 1.0. They are close to the tricritical mean field model, but no reliable fits were obtained in the martensite. The results are discussed in terms of microscopically different magnetic states in two alloys reflecting a complex interplay between the ferromagnetic and antiferromagnetic contributions.
    No preview · Article · May 2015 · Journal of Alloys and Compounds
  • Source
    Andoni Lasheras · Jon Gutiérrez · Jose Manuel Barandiarán · D. A. Shishkin · A. P. Potapov
    [Show abstract] [Hide abstract]
    ABSTRACT: Fabrication of magnetoelectric laminates to be used high sensitivity sensors is a critical task and turns out to be influenced by different factors. Among them, the length of the composite (that determines the working frequency of the device) and the epoxy glue characteristics and cure process (that determines the ME signal measured at high temperatures) are of great importance. Here we present results concerning the magnetoelectric response of laminate composites fabricated with an Fe61,6Co16,4Si10,8B11,2 amorphous alloy as the magnetostrictive component and the poly-vinylidene fluoride (PVDF) polymer as the piezoelectric one. Measurements have been performed with composites ranging from 3 cm to 1 cm length and from room temperature up to 100 °C. As observed, an appropriate gluing process between magnetostrictive and piezoelectric components assures the measured magnetoelectric signal to keep constant up to about 60 °C, a temperature where the α-relaxation of the PVDF occurs and the piezoelectric response starts decaying. On the other hand, magnetoelastic resonance (working) frequencies change from 67.5 KHz for the device with L=3 cm to 215 KHz (within the radio-frequency range) for the 1 cm long one. Even for the shortest laminate, we are still able to detect some 6 V/cm.Oe at 100 °C. This makes such laminate composites suitable for high temperature and high frequency applications.
    Full-text · Article · May 2015 · Key Engineering Materials

Publication Stats

5k Citations
808.77 Total Impact Points

Institutions

  • 1982-2016
    • Universidad del País Vasco / Euskal Herriko Unibertsitatea
      • • Departamento de Electricidad y Electrónica
      • • Facultad de Ciencia y Tecnología
      • • Departamento de Física de Materiales
      • • Physical Chemistry
      Leioa, Basque Country, Spain
  • 2014
    • Basque Center for Materials, Applications and Nanostructures
      Basque Country, Spain
  • 2012
    • Ikerbasque - Basque Foundation for Science
      Bilbo, Basque Country, Spain
  • 2008
    • Massachusetts Institute of Technology
      Cambridge, Massachusetts, United States
  • 1980-2001
    • Complutense University of Madrid
      • Instituto de Magnetismo Aplicado
      Madrid, Madrid, Spain
  • 1979-2001
    • Universidad de Navarra
      Iruña, Navarre, Spain
  • 2000
    • French National Centre for Scientific Research
      Lutetia Parisorum, Île-de-France, France
    • Klinikum St. Elisabeth Straubing GmbH
      Straubing, Bavaria, Germany
  • 1999
    • University of Campinas
      Conceição de Campinas, São Paulo, Brazil
  • 1990-1998
    • Universidad de Cantabria
      • Faculty of Sciences
      Santander, Cantabria, Spain
  • 1985
    • Technical University of Denmark
      Lyngby, Capital Region, Denmark