Listar por autoría "4211dce4-0fca-415e-b006-6693a6dde719"

Mostrando ítems 1-15 de 15

    • openAccess   Atmosphere- and Voltage-Dependent Electronic Conductivity of Oxide-Ion-Conducting Zr1-xYxO2-x/2 Ceramics 

      Jovaní, Marc; Beltrán Mir, Héctor; Cordoncillo, Eloisa; West, Anthony R. ACS (2017-05)
      Cubic, fluorite-structured solid solutions Zr1-xYxO2-x/2 (YSZ; x = 0.4-0.7) were prepared by sol-gel synthesis. Impedance measurements on pellets of 85% approximate density sintered at 1300 °C for 24 h showed strong evidence ...

    • openAccess   Enhanced conductivity and nonlinear voltage–current characteristics of nonstoichiometric BaTiO3 ceramics 

      Beltrán Mir, Héctor; Prades Tena, Marta; Masó, Nahum; West, Anthony R.; Cordoncillo, Eloisa Wiley-Blackwell (2011-03-21)
      The electrical conductivity of both BaO-deficient and TiO2-deficient BaTiO3 ceramics shows nonohmic, low-field characteristics at temperatures >∼200°C in contrast to stoichiometric BaTiO3 for which the electrical conductivity ...

    • openAccess   Field enhanced bulk conductivity of acceptor-doped BaTi1−xCaxO3−x ceramics 

      Masó, Nahum; Prades Tena, Marta; Beltrán Mir, Héctor; Cordoncillo, Eloisa; Sinclair, Derek C.; West, Anthony R. American Institute of Physics (2010)
      The electrical properties of Ca-doped BaTiO3 are very different when Ca substitutes onto Ba or Ti sites. The p-type semiconductivity of Ti-substituted ceramics increases reversibly by one to two orders of magnitude under ...

    • closedAccess   Field enhanced bulk conductivity of BaTiO3 : Mg ceramics 

      Prades Tena, Marta; Masó, Nahum; Beltrán Mir, Héctor; Cordoncillo, Eloisa; West, Anthony R. Royal Society of Chemistry (2010)
      The electrical conductivity of ceramics of composition Ba(Ti1−xMgx)O3−x: 0.00003 ≤ x ≤ 0.01 increases with time on application of a small dc bias voltage in the range 1 to 50 V cm−1 and at temperatures in the range 200 to ...

    • openAccess   Field-enhanced bulk conductivity and resistive-switching in Ca-doped BiFeO3 ceramics 

      Masó, Nahum; Beltrán Mir, Héctor; Prades Tena, Marta; Cordoncillo, Eloisa; West, Anthony R. Royal Society of Chemistry (2014)
      The bulk conductivity at room temperature of Ca-doped BiFeO3 ceramics is p-type and increases reversibly by up to 3 orders of magnitude under the influence of a small dc bias voltage in the range B3 to 20 V mm1 . The ...

    • openAccess   Field-induced p-n transition in yttria-stabilized zirconia 

      Jovaní, Marc; Beltrán Mir, Héctor; Cordoncillo, Eloisa; West, Anthony R. Nature (2019)
      Oxide ion conducting yttria-stabilised zirconia ceramics show the onset of electronic conduction under a small bias voltage. Compositions with a high yttria content undergo a transition from p-type to n-type behavior at ...

    • openAccess   Non-Ohmic Phenomena in Mn-doped BaTiO3 

      Prades Tena, Marta; Beltrán Mir, Héctor; Cordoncillo, Eloisa; Alonso, Pablo J.; Masó, Nahum; West, Anthony R. Wiley-Blackwell (2012)
      We report here a novel effect in which the resistance of a semiconducting oxide ceramic increases on application of a small dc bias. The ceramic conducts at high temperatures by an n-type hopping mechanism. On application ...

    • openAccess   Phase transition hysteresis and anomalous Curie-Weis behavior of ferroelectric tetragonaltungsten bronzes Ba2RETi2Nb3O15:RE=Nd, Sm 

      Prades Tena, Marta; Beltrán Mir, Héctor; Masó, Nahum; Cordoncillo, Eloisa; West, Anthony R. American Institute of Physics (2008)
      The ferroelectric tetragonal tungsten bronze TTB phases, Ba2RETi2Nb3O15 :RE=Nd,Sm, were prepared by low temperature solvothermal synthesis. The permittivity versus temperature data of sintered ceramics show two unusual ...

    • closedAccess   Polymorphism and Dielectric Properties of Nb-Doped BaTiO3 

      Masó, Nahum; Beltrán Mir, Héctor; Cordoncillo, Eloisa; Sinclair, Derek C.; West, Anthony R. Wiley (2008-01)
      A working subsolidus phase diagram for the system BaTiO3–Ba5Nb4O15 has been determined by firing sol–gel-synthesized samples over a range of temperatures. The main difference from previous diagrams is the greater extent ...

    • closedAccess   Polymorphism of BaTiO3 Acceptor Doped with Mn3+, Fe3+, and Ti3+ 

      Prades Tena, Marta; Masó, Nahum; Beltrán Mir, Héctor; Cordoncillo, Eloisa; West, Anthony R. Wiley (2008-07)
      The effect of Mn doping on the cubic to hexagonal phase transition temperature in BaTiO3 has been determined by quenching samples with different Mn contents from a range of temperatures. Under conditions of equilibrating ...

    • openAccess   Site-selective symmetries of Eu3+-doped BaTiO3 ceramics: a structural elucidation by optical spectroscopy 

      Serna-Gallén, Pablo; Beltrán Mir, Héctor; Cordoncillo, Eloisa; West, Anthony R.; Balda, Rolindes; FERNANDEZ RODRIGUEZ, JOAQUIN MANUEL Royal Society of Chemistry (2019-10-22)
      Eu3+-Doped BaTiO3 ceramics with dopant contents between 0 and 10 mol% were prepared by sol–gel synthesis based on the nominal compositions (Ba1−3xEu2x)TiO3 and Ba(Ti1−xEux)O3−x/2, where two possible substitution mechanisms ...

    • openAccess   Spinel–rock salt transformation in LiCoMnO4−δ 

      Reeves-McLaren, Nik; Sharp, Joanne; Beltrán Mir, Héctor; Rainforth, William; West, Anthony R. The Royal Society (2016)
      The transformation on heating LiCoMnO4, with a spinel structure, to LiCoMnO3, with a cationdisordered rock salt structure, accompanied by loss of 25% of the oxygen, has been followed using a combination of diffraction, ...

    • closedAccess   Synthesis, Structural Characterization, and Electrical Properties of New Oxygen-Deficient Tetragonal Tungsten Bronzes Ba2NdTi2+xNb3–xO15–x/2 

      Prades Tena, Marta; Masó, Nahum; Beltrán Mir, Héctor; Cordoncillo, Eloisa; West, Anthony R. American Chemical Society (2013)
      Oxygen-deficient tetragonal tungsten bronzes ceramics with general formula Ba2NdTi2+xNb3–xO15–x/2 (0 ≤ x ≤ 1) have been prepared by low temperature solvothermal synthesis with final firing of ceramics at 1100–1300 °C in ...

    • openAccess   Voltage-Dependent Bulk Resistivity of SrTiO3:Mg Ceramics 

      Gil Escrig, Lidon; Prades Tena, Marta; Beltrán Mir, Héctor; Cordoncillo, Eloisa; Masó, Nahum; West, Anthony R. John Wiley & Sons (2014)
      Single phase ceramics of composition Sr(Ti1–xMgx)O3–x: 0 ≤ x ≤ 0.01 were prepared by sol–gel synthesis and characterized by X-ray diffraction, scanning electron microscopy, impedance spectroscopy, and current–voltage ...

    • closedAccess   Voltage-Dependent Low-Field Bulk Resistivity in BaTiO3:Zn Ceramics 

      Beltrán Mir, Héctor; Prades Tena, Marta; Masó, Nahum; Cordoncillo, Eloisa; West, Anthony R. American Ceramic Society (2010-02)
      Ceramics of composition Ba(Ti1−xZnx)O3−x: 0.00003≤x≤0.01 exhibit modest semiconductivity, whose value is increased by up to two orders of magnitude under the action of a small dc bias voltage. The effect, which is not ...