Navegação Ciências Exatas e da Terra por Assunto "Magnetorresistência"

Resultados 1-20 de 27

    • Bias dependence of magnetoresistance in Fe-Al/sub 2/O/sub 3/ granular thin films 

      Boff, Marco Aurelio Silveira; Geshev, Julian Penkov; Schmidt, Joao Edgar; Flores, Wladimir Hernandez; Antunes, Arlei Borba; Gusmao, Miguel Angelo Cavalheiro; Teixeira, Sergio Ribeiro (2002) [Artigo de periódico]
      This paper reports on the magnetotransport behavior of Fe–Al2O3 granular thin films when the injected dc current is varied. The electric resistance as a function of temperature, magnetoresistance, and the current vs applied ...

    • Calculation of the temperature dependence of the giant mr and application to Co/Cu multilayers 

      Duvail, Jean-Luc; Fert, Albert R.; Pereira, Luis Gustavo; Lottis, Daniel Kurt (1994) [Artigo de periódico]
      Most theoretical models of the giant magnetoresistance (GMR) in metallic magnetic multilayers developed up to now are for the zero-temperature limit, thus neglecting the spin-flip scattering arising from spin fluctuations ...

    • Co/ag multilayer film : role of annealing on the magnetic properties 

      Schelp, Luiz Fernando; Tosin, Giancarlo; Carara, Marcos Andre; Baibich, Mario Norberto; Gomes, Affonso Augusto Guidão; Schmidt, Joao Edgar (1992) [Artigo de periódico]
      Co( 15 A)/Ag(60 A) multilayers produced by electron beam deposition on a 50 A chromium buffer layer over a Si( 111) wafer have been studied by magnetoresistance, saturation magnetization, coercivity, and anisotropy. Annealing ...

    • Correlation between magnetic interactions and giant magnetoresistance in melt-spun co/sub 10/cu/sub 90/ granular alloys 

      Viegas, Alexandre da Cas; Geshev, Julian Penkov; Dorneles, Lucio Strazzabosco; Schmidt, Joao Edgar; Knobel, Marcelo (1997) [Artigo de periódico]
      The effects of annealing on the structural, magnetic, and magnetotransport properties of melt-spun Co10Cu90 granular alloys were investigated. The interaction effects were studied from both remanent magnetization and ...

    • Correlation between the magnetic irreversibility limit and the zero resistance point in different granular YBa/sub 2/Cu/sub 3/O/sub 7-σ superconductors 

      Dias, Fabio Teixeira; Vieira, Valdemar das Neves; Rodrigues Junior, Pedro; Obradors, Xavier; Pureur Neto, Paulo; Schaf, Jacob (2008) [Artigo de periódico]
      We report on magnetization and magnetoresistance measurements of single-crystal, melt-processed, and polycrystalline YBa2Cu3O7− samples with the purpose of disclosing the connection between the magnetic irreversibility ...

    • De Haas-van Alphen oscillations and magnetic breakdown : semiclassical calculation of multiband orbits 

      Fortin, Jean-Yves; Belissard, Jean; Gusmao, Miguel Angelo Cavalheiro; Ziman, Timothy (1998) [Artigo de periódico]
      We use an algebraic method to compute de Haas–van Alphen oscillations in two-dimensional systems in the semiclassical approximation for cases where the Fermi surface lies on more than one sheet of the energy surface. We ...

    • Discrimination between coupling and anisotropy fields in exchange-biased bilayers 

      Geshev, Julian Penkov; Nicolodi, Sabrina; Silva, Ricardo Barreto da; Nogués Sanmiquel, Josep; Skumryev, Vassil; Baró, Maria Dolors (2009) [Artigo de periódico]
      In the framework of models that assume planar domain wall formed at the antiferromagnetic part of the interface of exchange-biased bilayers, one cannot distinguish between the cases of high or low ratios between the coupling ...

    • Electrical magnetotransport properties in RCo12B6 compounds (R = Y, Gd, and Ho) 

      Mesquita, Fabiano; Magalhaes, Sergio Garcia; Pureur Neto, Paulo; Diop, Léopold Vincent Birane; Isnard, Olivier (2020) [Artigo de periódico]
      Remarkable electronic transport and magnetotransport properties are found in the intermetallic compounds RCo12B6 (R=Y, Ho, and Gd). Detailed resistivity, magnetoresistance, and Hall effect measurements are reported in the ...

    • Epitaxial spin-valve structures for ultra-low-field detection 

      Schuhl, A.; Durand, Olivier; Childress, J.R.; George, Jean-Marie; Pereira, Luis Gustavo (1994) [Artigo de periódico]
      A new epitaxial “spin-valve”-type system for low-field magnetoresistive detection is described. This system is based on FeiPd epitaxial multilayers grown on (100)MgO by MBE. These films show a very abrupt transition from ...

    • Extremely large magnetic-field-effects on the impedance response of TiO2 quantum dots 

      Mombrú, Dominique; Romero, Mariano; Faccio, Ricardo; Tumelero, Milton André; Mombrú, Álvaro W. (2019) [Artigo de periódico]
      Here, we report large magnetoresistance and magnetocapacitance response of undoped TiO 2 quantum dots weighting the contribution of both grain and grain boundaries by means of impedance spectroscopy. We also performed a ...

    • Fluctuation magnetoconductivity in YBa/sub 2/Cu/sub 3/O/sub 7/ : Gaussian, three-dimensional XY, beyond three-dimensional XY, and lowest-Landau-level scaling 

      Costa, Rosangela Menegotto; Pureur Neto, Paulo; Gusmao, Miguel Angelo Cavalheiro; Senoussi, Sadok; Behnia, K. (2001) [Artigo de periódico]
      Systematic measurements of the in-plane fluctuation magnetoconductivity in a YBa₂Cu₃O₇ single crystal are presented. Fields between 0 and 14 T were applied either parallel or perpendicular to the Cu-O atomic planes. The ...

    • Giant magnetoresistance and remanence in granular cocu codeposited films 

      Viegas, Alexandre da Cas; Geshev, Julian Penkov; Schmidt, Joao Edgar; Ferrari, Edson Fernando (1998) [Artigo de periódico]
      We present experimental magnetoresistance, magnetization, and remanence data for CoCu granular films obtained by electron beam codeposition, subsequently submitted to a thermal treatment. The magnetization measurements ...

    • Heavily n-doped Ge : low-temperature magnetoresistance properties on the metallic side of the metal–nonmetal transition 

      Silva, Antonio Ferreira da; Sandoval, Marcelo A. Toloza; Levine, Alexandre; Levinson, Eduard; Boudinov, Henri Ivanov; Sernelius, Bo E. (2020) [Artigo de periódico]
      We report here an experimental and theoretical study on the magnetoresistance properties of heavily phosphorous doped germanium on the metallic side of the metal–nonmetal transition. An anomalous regime, formed by negative ...

    • Inverse spin-valve-type magnetoresistance in spin engineered multilayered structures 

      George, Jean-Marie; Pereira, Luis Gustavo; Barthelemy, Agnès; Petroff, Frédéric; Steren, Laura; Duvail, Jean-Luc; Fert, Albert R.; Loloee, Reza; Holody, Paul; Schroeder, Peter A. (1994) [Artigo de periódico]
      The resistivity of magnetic multilayers is generally smaller when the magnetizations of successive layers are parallel, which is the so-called giant magnetoresistance or spin-valve effect. We have been able to reverse this ...

    • Low potential barrier height effects in magnetic tunneling junctions 

      Cruz de Gracia, Evgeni Svenk; Dorneles, Lucio Strazzabosco; Schelp, Luiz Fernando; Teixeira, Sergio Ribeiro; Baibich, Mario Norberto (2007) [Artigo de periódico]
      This paper reports on the study of deposited (Ni81Fe19/AlOx /Co) magnetic tunnel junctions by magnetron sputtering, with the insulating layer obtained by plasma oxidation of Al. Concentration of the tunnel current in small ...

    • Magnetism in dilute magnetic oxide thin films based on SnO/sub 2/ 

      Fitzgerald, C.B.; Venkatesan, M.; Dorneles, Lucio Strazzabosco; Gunning, R.; Stamenov, Plamen; Coey, John Michael Douglas; Stampe, P.A.; Kennedy, R.J.; Moreira, Eduardo Ceretta; Sias, Uilson Schwantz (2006) [Artigo de periódico]
      Thin films of SnO2 prepared by pulsed-laser deposition on R-cut sapphire substrates exhibit ferromagnetic properties at room temperature when they are doped with Cr, Mn, Fe, Co, or Ni, but not with other 3d cations. ...

    • Magnetoresistance in rf-sputtered(nife/cu/co/cu) spin-valve multilayers 

      Lottis, Daniel Kurt; Fert, Albert R.; Morel, Robert; Pereira, Luis Gustavo; Jacquet, J.C.; Galtier, P.; Coutellier, J.M.; Valet, Tierry (1993) [Artigo de periódico]
      A study of the vtiation of the magnetoresistancein (Ni80Fe20/Cu/Co/Cu) multilayers with the thicknesses tNiFe, tcO, and &;cu of each type of component layer has been performed. The magnetoresistance (MR), which at 4 .2 K ...

    • Magnetoresistance of doped silicon 

      Silva, Antonio Ferreira da; Levine, Alexandre; Momtaz, Zahra Sadre; Boudinov, Henri Ivanov; Sernelius, Bo E. (2015) [Artigo de periódico]
      We have performed longitudinal magnetoresistance measurements on heavily n-doped silicon for donor concentrations exceeding the critical value for the metal-nonmetal transition. The results are compared to those from a ...

    • Magnetoresistance of pd-fe and pd-ni-fe alloys 

      Hsu, Y.; Schmidt, Joao Edgar; Gupta, M.; Jen, S.; Berger, Luc (1983) [Artigo de periódico]
      The electrical resistivity ofPd-Fe alloys has been measured in magnetic fields parallel and perpendicular to the current, for a wide range of alloy compositions. The influence of atomic ordering on the magnetoresistance ...

    • Magnetotransport properties in the magnetic phase of BaFe2−xTxAs2 (T = Co,Ni) : a magnetic excitations approach 

      Peña Pacheco, Jully Paola; Piva, M. M.; Rosa, P. F. S.; Pagliuso, P. G.; Adriano, C.; Grant, Ted W.; Fisk, Zachary; Baggio-Saitovitch, E.; Pureur Neto, Paulo (2018) [Artigo de periódico]
      Because of their complex Fermi surfaces, the identification of the physical phenomena contributing to electronic scattering in the Fe-based superconductors is a difficult task. Here, we report on the electrical resistivity, ...