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Magnetic and electrical properties of ferromagnetic nanocomposites based on Co nanoparticles in Al 2 O 3 matrix
Author(s) -
Radchenko M. V.,
Lashkarev G. V.,
Bugaiova M. E.,
Sichkovskyi V. I.,
Lazorenko V. I.,
Stelmakh Y. A.,
Krushynskaya L. A.,
Knoff W.,
Story T.,
Kolesnik S. P.,
Danylenko N. I.
Publication year - 2011
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201001127
Subject(s) - materials science , superparamagnetism , ferromagnetism , magnetoresistance , ferromagnetic resonance , electrical resistivity and conductivity , paramagnetism , condensed matter physics , nanocomposite , nanoparticle , variable range hopping , squid , analytical chemistry (journal) , magnetization , magnetic field , nanotechnology , composite material , chemistry , thermal conduction , ecology , physics , engineering , quantum mechanics , electrical engineering , biology , chromatography
Magnetic, structural, and electrical properties are reported for ferromagnetic nanocomposites (FMNC) consisting of nanometer size Co ferromagnetic nanoparticles (NP) embedded in Al 2 O 3 dielectric matrix. Co x (Al 2 O 3 ) 100− x FMNC with x = 7.8, 28.2, and 42.2 at.% were obtained in the form of (1–5) µm thick films by modified electron beam physical vapor deposition of Al 2 O 3 and Co vapors condensing on policor substrate at temperatures 100–400 °C. Magnetic properties of these FMNC studied by SQUID magnetometry and ferromagnetic resonance (FMR) methods revealed paramagnetic properties for layers with x = 7.8 at.%, superparamagnetic behavior for x = 28.2 at.%, and ferromagnetic state for the highest Co concentration studied x = 42.2 at.%. Temperature dependence of electrical conductivity in FMNC with low Co content was found to follow the Mott law for variable range hopping mechanism. Magnetic field dependence of resistivity revealed a negative magnetoresistance effect. These results confirm the effectiveness of the applied technology for the preparation of Co x (Al 2 O 3 ) 100− x FMNC.