Navegação Ciências Exatas e da Terra por Autor "Cunha, Joao Batista Marimon da"

Resultados 1-14 de 14

    • Bicriticality in Fe/sub x/Co/sub 1-x/Ta/sub 2/O/sub 6/ 

      Kinast, Eder Julio; Antonietti, Volmir; Schmitt, Denys; Isnard, Olivier; Cunha, Joao Batista Marimon da; Gusmao, Miguel Angelo Cavalheiro; Santos, Carlos Alberto dos (2003) [Artigo de periódico]
      X-ray and neutron-diffraction, dc magnetic susceptibility, magnetization, and specific-heat measurements are reported for FexCo1 xTa2O6 mixed oxides. X-ray refinement indicates homogeneous samples for all the reported ...

    • Crystal chemistry and structure of the orthorhombic (Fe, Mn)(Ta, Nb)/sub 2/O/sub 6/ family of compounds 

      Santos, Carlos Alberto dos; Zawislak, Luci Irene; Kinast, Eder Julio; Antonietti, Volmir; Cunha, Joao Batista Marimon da (2001) [Artigo de periódico]
      In this paper we review the crystal chemistry and structure data from the literature and our results reported in the last decade for natural and synthetic samples of the tantalite-columbite series. Orderdisorder transitions ...

    • Dimensional crossover in magnetic warwickites 

      Guimaraes, Renato Bastos; Fernandes, Joao Carlos; Continentino, Mucio Amado; Borges, Hortencio A.; Moura, Cassio Stein; Cunha, Joao Batista Marimon da; Santos, Carlos Alberto dos (1997) [Artigo de periódico]
      We present an investigation of the magnetic properties of a series of warwickites with different transition metals. These materials are characterized by one-dimensional structures called ribbons where the transition metals ...

    • Effect of interface intermixing on giant magnetoresistance in NiFe/Cu and Co/NiFe/Co/Cu multilayers 

      Nagamine, Luiz Carlos Camargo Miranda; Biondo Filho, Armando; Pereira, Luis Gustavo; Silva, Alexandre Mello de Paula; Schmidt, Joao Edgar; Chimendes, Tiago Walescko; Cunha, Joao Batista Marimon da; Baggio-Saitovitch, E. (2003) [Artigo de periódico]
      This article reports on the important influence of the spontaneously built-in paramagnetic interfacial layers on the magnetic and magnetoresistive properties of NiFe/Cu and Co/NiFe/Co/Cu multilayers grown by magnetron ...

    • Influence of annealing on magnesioferrite nanoparticles synthesized by a sol-gel/combustion method 

      Biasi, Ronaldo Sergio de; Cardoso, Lúcia Helena Guimarães; Campos, José Brant de; Sanchez Candela, Dalber Ruben; Cunha, Joao Batista Marimon da (2009) [Artigo de periódico]
      Nanocrystalline particles of magnesioferrite (MgFe2O4) were prepared by a sol-gel/combustion method using iron nitrate, Fe(NO3)3.9H2O, magnesium nitrate, Mg(NO3)2.6H2O, and citric acid, C6H8O7.H2O, and annealed for 2 hours ...

    • Low-dimensional magnetic properties of orthorhombic MnV2O6 : a nonstandard structure stabilized at high pressure 

      Hneda, Marlon Luiz; Cunha, Joao Batista Marimon da; Gusmao, Miguel Angelo Cavalheiro; Oliveira Neto, Samuel Rodrigues de; Rodríguez-Carvajal, Juan; Isnard, Olivier (2017) [Artigo de periódico]

    • Magnetic behavior of the NixFe1−xNb2O6 quasi-one-dimensional system : isolation of Ising chains by frustration 

      Sarvezuk, Paulo Willian Carvalho; Gusmao, Miguel Angelo Cavalheiro; Cunha, Joao Batista Marimon da; Isnard, Olivier (2012) [Artigo de periódico]
      Physical properties of the NixFe1−xNb2O6 compounds are investigated combining x-ray and neutron powder diffraction with magnetic and calorimetry measurements as well as 57Fe Mössbauer spectroscopy. This system is known to ...

    • Magnetic interactions in the ludwigite Ni/sub 2/FeO/sub 2/BO/sub 3/ 

      Fernandes, Joao Carlos; Guimaraes, Renato Bastos; Continentino, Mucio Amado; Borges, Hortencio A.; Sulpice, A.; Tholence, Jean-Louis; Siqueira, Jesumar Lopes; Zawislak, Luci Irene; Cunha, Joao Batista Marimon da; Santos, Carlos Alberto dos (1998) [Artigo de periódico]
      We present an investigation of the magnetic properties of the ludwigite Ni2FeO2BO3. This material is an oxyborate that presents in its crystalline structure subunits in the form of walls where the transition metal ions are ...

    • A new approach for the determination of multiple cation locations and ordering, using the example of natural and heat-treated columbites 

      Kinast, Eder Julio; Isnard, Olivier; Cunha, Joao Batista Marimon da; Vasconcellos, Marcos Antonio Zen; Santos, Carlos Alberto dos (2011) [Artigo de periódico]
      A new approach is proposed to determine unambiguously the location of four cations within the crystal structure of a natural AB2O6 columbite-type compound and derivatives, when submitted to order–disorder transitions caused ...

    • Peculiarity of a magnetic structure in a quasi-one-dimensional columbite Co0.4Ni0.6Nb2O6 

      Sarvezuk, Paulo Willian Carvalho; Cunha, Joao Batista Marimon da; Isnard, Olivier (2020) [Artigo de periódico]
      Quasi-one-dimensional (Q1D) spin chain systems have great potential applications in high-density information storage devices, quantum information and computers, because of their quantum magnetism properties. The low-dimensional ...

    • Phase evolution and magnetic properties of a high-energy ball-milled hematite-alumina system 

      Cótica, Luiz Fernando; Zanatta, Shalimar Calegarri; Rocha, Maria Aparecida; Santos, Ivanir Aparecido dos; Paesano Junior, Andrea; Cunha, Joao Batista Marimon da; Hallouche, Bachir (2004) [Artigo de periódico]

    • Structural and Mössbauer characterization of the ball-milled Fe/sub x/(Al/sub 2/O/sub 3)/sub 100-x/ system 

      Paesano Junior, Andrea; Matsuda, Célia Kimie; Cótica, Luiz Fernando; Medeiros, Suzana Nóbrega de; Cunha, Joao Batista Marimon da; Hallouche, Bachir; Silva, Selma Luiza (2004) [Artigo de periódico]
      Metal-oxide composites were synthesized by high-energy ball milling of metallic iron (α-Fe) and alumina (α-Al2O3) powders, varying the starting relative concentration and the milling time. The samples were characterized ...

    • Suppression of magnetic ordering in quasi-one-dimensional FexCo1−xNb2O6 compounds 

      Sarvezuk, Paulo Willian Carvalho; Kinast, Eder Julio; Colin, C. V.; Gusmao, Miguel Angelo Cavalheiro; Cunha, Joao Batista Marimon da; Isnard, Olivier (2011) [Artigo de periódico]
      We present a systematic investigation of the series of compounds FexCo1−xNb2O6 by means of x-ray and neutron powder diffraction combined with magnetic measurements, carried out in the paramagnetic as well as in the ordered ...

    • X-ray-absorption spectroscopy and x-ray diffraction in discontinuous Co/sub x/Fe/sub 1-x//Ag multilayers 

      Flores, Wladimir Hernandez; Teixeira, Sergio Ribeiro; Cunha, Joao Batista Marimon da; Alves, Maria do Carmo Martins; Tolentino, Hélio Cesar Nogueira; Traverse, Agnes (2000) [Artigo de periódico]
      This paper reports on the structural properties of CoxFe12x /Ag discontinuous multilayers with x 50, 0.3, 0.7, and 1. The evolution of the structural properties has been investigated by x-ray diffraction and x-ray-absorption ...