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Ferromagnetism in multilayered graphite nanostructures doped with nitrogen

ORAL

Abstract

Carbon microspheres consisting of multilayered nanographite structures are prepared using solid-phase pyrolysis of metal-free phthalocyanine H2(C32N8H16). The mean diameter d=3±0.2μm of carbon microspheres have been obtained at pyrolysis Tpyr =670oC, and tpyr =30min. Morphology and structure of prepared samples at two temperatures Tpyr were investigated by HRTEM, X-ray diffractometry, Raman and XPS spectroscopy. Magnetic properties of samples were investigated using vibrational magnetometer and magnetic fields up to 80 kOe, as well as X-band ESR spectrometer in range of temperature, T=5-300K. We found that the temperature dependences of saturation magnetization closely follow the behavior of integrated magnetic resonance intensity. Parameters of ESR spectrum are following g-factor 2.0031, intensity ~5×1019 spin/g and narrow linewidth of 0.8Oe due to strong exchange. Maximum values of saturation magnetization Ms≈0.03emu/g and coercive force Hc=400Oe have been obtained at 25K. The results suggest that observed ferromagnetism in multilayer graphene can be attributed to nitrogen atoms and zigzag edges.

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Presenters

  • Armen Kocharian

    CAL State University, Los Angeles, Physics Department, Russian-Armenian (Slavonic) University, Yerevan

Authors

  • Aram Manukyan

    CAL State University, Los Angeles, Physics Department, Russian-Armenian (Slavonic) University, Yerevan

  • Harutyun Gyulasaryan

    Physics, Russian-Armenian (Slavonic) University, Yerevan, Armenia, Physics Department, Russian-Armenian (Slavonic) University, Yerevan

  • Eduard Sharoyan

    Laboratory of Solid State Physics, Armenia, Institute for Physical Research, NAS of Armenia, Institute of Physical Research, NAS of Armenia, Laboratory of Solid State Physics, Ashtarak

  • Paul Oyala

    Division of Chemistry and Chemical Engineering,, California Institute of Technology, Pasadena, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena

  • Oscar Bernal

    CAL State University, Los Angeles, Physics, California State University, Los Angeles, Cal State Univ LA

  • Armen Kocharian

    CAL State University, Los Angeles, Physics Department, Russian-Armenian (Slavonic) University, Yerevan