Listar Ciencias Exactas y Naturales por autor "Pureur Neto, Paulo"
Mostrando ítems 1-20 de 27
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Anisotropic rare-earth spin-glasses
Fert, Albert R.; Pureur Neto, Paulo; Hippert, F.; Baberschke, Klaus; Bruss, F. (1982) [Artículo de periódico]We present magnetic measurements (ac and de susceptibilities and magnetization) on YEr and YGd single crystals. The longitudinal (i.e., along the c axis) susceptibility of YEr shows a typical spin-glass-like cusp, whereas ... -
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) [Artículo 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 ... -
Critical and gaussian conductivity fluctuations in yba2cu3o7-delta
Pureur Neto, Paulo; Costa, Rosangela Menegotto; Rodrigues Junior, Pedro; Schaf, Jacob; Kunzler, Julio Vitor (1993) [Artículo de periódico]We report on systematic conductivity fluctuation measurements on three different samp1es of YBa2Cu30 7 - δ • We show, using the temperature derivative of the resistivity and the logarithmic derivative ofthe conductivity ... -
Effects of Ca and Sr chemical doping on the average superconducting kinetic energy of YBa2Cu3O7-δ
Vieira, Valdemar das Neves; Mendonça, A.P.A.; Dias, Fabio Teixeira; Hneda, Marlon Luiz; Pureur Neto, Paulo; Schaf, Jacob; Mesquita, Fabiano (2015) [Artículo de periódico]In this brief communication we applied the MZFC(T) and MFCC(T) reversible dc magnetizations to get the average superconducting kinetic energy density, kS(T,B) of YBa2Cu3O7-d, Y0.95Ca0.05Ba2Cu3O7-d and YBa1.75Sr0.25Cu3O7-d ... -
Effects of pressure on the fluctuation conductivity of YBa/sub 2/Cu/sub 3/O/sub 7/
Ferreira, Leticie Mendonca; Pureur Neto, Paulo; Borges, Hortencio A.; Lejay, Pascal (2004) [Artículo de periódico]The effects of hydrostatic pressure up to 1.11 GPa on the in-plane fluctuation conductivity of YBa2Cu3O7−d are investigated. The experiments are focused on the asymptotic region closely above Tc where a threedimensional ... -
Effects of Zn and Mg in Cu sites of YBa/sub 2/Cu/sub 3/O/sub 7-[delta]/ single crystals on the resistive transition, fluctuation conductivity, and magnetic irreversibilities
Vieira, Valdemar das Neves; Pureur Neto, Paulo; Schaf, Jacob (2002) [Artículo de periódico]We report on the resistive transition and fluctuation conductivity of an YBa2Cu2.97Zn0.03O7-δ single crystal and on the magnetic irreversibilities of this compound in two different oxygen states and another YBa2Cu3O7-δ ... -
Electrical magnetotransport properties in RCo12B6 compounds (R = Y, Gd, and Ho)
Mesquita, Fabiano; Magalhães, Sergio Garcia; Pureur Neto, Paulo; Diop, Léopold Vincent Birane; Isnard, Olivier (2020) [Artículo 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 ... -
Evidence of spin-density-wave to spin-glass transformation in ynd alloys
Trovarelli, O.; Sereni, J.G.; Pureur Neto, Paulo; Schaf, Jacob (1995) [Artículo de periódico]Low-temperature ac and de magnetic susceptibility and specific-heat measurements have been carried out on YNd di1ute alloys, where the Nd concentrations are 1.9, 2.5, 4.5, 6.8, and 9.0 at. %. The most concentrated alloys ... -
Field and oxygen dependence of the magnetic irreversibility line in yba(2)cu(3)o(7-g)
Rodrigues Junior, Pedro; Schaf, Jacob; Pureur Neto, Paulo (1994) [Artículo de periódico]We report on de magnetic susceptibility measurements in polycrystalline YBa2Cu30 7- δ as a function of the oxygen content in the limit of small δ. We focus mainly on the detailed behavior of the zero-fie1dcooled- field-cooled ... -
Fluctuation conductivity and microscopic granularity in bi-based high-temperature superconductors
Jurelo, Alcione Roberto; Kunzler, Julio Vitor; Schaf, Jacob; Pureur Neto, Paulo; Rosenblatt, Jorge (1997) [Artículo de periódico]Systematic conductivity measurements near Tc in granular (Bi,Pb)-Sr-Ca-Cu-O superconductors are presented, and focus is given on the interplay between thermal fluctuations and disorder at micro- and mesoscopic levels. ... -
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) [Artículo 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 ... -
Gaussian, three-dimensional-xy, and lowest-landau-level scalings in the low-field fluctuation magnetoconductivity of bi/sub 2/ sr/sub 2/ cacu/sub 2/ o/sub 8/
Costa, Rosangela Menegotto; Pureur Neto, Paulo; Ghivelder, Luis; Campa, J.A.; Rasines, I. (1997) [Artículo de periódico]Systematic measurements of low-field fluctuation magnetoconductivity in a single crystal of Bi2Sr2CaCu2O8 are reported. Gaussian, critical, and lowest-Landau-level scalings are observed. In the Gaussian regimes, large ... -
Glass behavior and the h-t phase diagram of the high-tc ceramic superconductors yba2cu3o7, euba2cu3o7 and gdba2cu3o7
Schaf, Jacob; Pureur Neto, Paulo; Kunzler, Julio Vitor (1989) [Artículo de periódico]We report systematic field-cooled (PC) and zero-field-cooled (ZPC) diamagnetic susceptibility measurements in polycrystalline samples of the high-Tc oxide superconductors RBa2Cu30 7, where R =Y, Eu, or Gd. We focus mainly ... -
Hall effect in Ce 1-x Y x/Pd 3 mixed-valence alloys
Fert, Albert R.; Pureur Neto, Paulo; Hamzic, Amir; Kappler, J.P. (1985) [Artículo de periódico]Mixed-valence and Kondo lattice systems exhibit large anomalous Hall coefficients with a striking change of sign at low temperature in severa! systems (CePd3, CeCu6, ... , etc.). We have studied the Hall effect of Ce1-x ... -
Impedance and initial magnetic permeability of gadolinium
Fraga, Gilberto Luiz Ferreira; Pureur Neto, Paulo; Cardoso, Lisandro Pavie (2010) [Artículo de periódico]In the present work we report on measurements of the complex impedance and the magnetoimpedance of a textured sample of gadolinium metal. The preferential c -axis orientation of the Gd hexagonal structure is perpendicular ... -
Impedance and initial magnetic permeability of the Heusler compounds Pd/sub 2/MnSn and Pd/sub 2/MnSb near the Curie temperature
Fraga, Gilberto Luiz Ferreira; Borba, Luciano Apellaniz; Pureur Neto, Paulo (2006) [Artículo de periódico]In this paper we report measurements of the complex impedance of the Heusler compounds Pd2MnSn and Pd2MnSb near the Curie temperature. From the experimental data, the complex initial magnetic permeability is obtained as a ... -
Magnetic ordering in YGd alloys
Pureur Neto, Paulo; Fert, Albert R.; Wendler, R.; Baberschke, Klaus (1985) [Artículo de periódico]We present magnetization and resistivity measurements on single crystals of yttrium doped with small concentrations of gadolinium (c = 1, 2, and 3 at. %). The low-field susceptibility exhibits a spin-glass-like sharp cusp ... -
Magnetism, magnetoresistance, and Shubnikov-de Haas oscillations in Na-implanted highly oriented pyrolitic graphite
Pires, Rafael Fernando; Pureur Neto, Paulo; Behar, Moni; Pimentel Junior, Jorge Luiz; Schaf, Jacob; Kopelevich, Y. (2012) [Artículo de periódico]We report on magnetization, magnetoresistance, and Shubnikov-de Haas oscillations experiments in Na-implanted samples of highly oriented pyrolitic graphite (HOPG). Different ion fluences were applied so that samples with ... -
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) [Artículo 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, ... -
Mechanical properties of highly oriented FeSe0.5Te0.5 superconductor
Pimentel Junior, Jorge Luiz; Pureur Neto, Paulo; Lopes, Cristiano Santos; Serbena, Francisco Carlos; Foerster, Carlos Eugenio; Silva, Simone Aparecida da; Jurelo, Alcione Roberto; Chinelatto, Adilson Luiz (2012) [Artículo de periódico]We have synthesized highly oriented samples of the superconducting compound FeSe0.5Te0.5 and investigated its mechanical properties. These samples were characterized by scanning electron microscopy (SEM) with energy-dispersive ...