Non-conductive ferromagnetic carbon-coated (Co, Ni) metal/polystyrene nanocomposites films

Journal Article · Mon Mar 07 04:00:00 EST 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4942862· OSTI ID:22597006

Viala, B.; Hermán, V. ^[1]; Tortai, J. -H. ^[2]; Duclairoir, F. ^[3]

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1. CEA, LETI, MINATEC Campus, Grenoble 38054 (France)
2. LTM-CNRS-UJF, CEA, LETI, Minatec Campus, Grenoble 38054 (France)
3. Université Grenoble Alpes, INAC, Grenoble 38054 (France)

This article reports non-conductive ferromagnetic properties of metal/polymer nanocomposite films intended to be used for RF applications. The nanocomposite arrangement is unique showing a core double-shell structure of metal-carbon-polystyrene: M/C//P{sub 1}/P{sub 2}, where M = Co, Ni is the core material, C = graphene or carbon is the first shell acting as a protective layer against oxidation, P{sub 1} = pyrene-terminated polystyrene is the second shell for electrical insulation, and P{sub 2} = polystyrene is a supporting matrix (// indicates actual grafting). The nanocomposite formulation is briefly described, and the film deposition by spin-coating is detailed. Original spin-curves are reported and analyzed. One key outcome is the achievement of uniform and cohesive films at the wafer scale. Structural properties of films are thoroughly detailed, and weight and volume fractions of M/C are considered. Then, a comprehensive overview of DC magnetic and electrical properties is reported. A discussion follows on the magnetic softness of the nanocomposites vs. that of a single particle (theoretical) and the raw powder (experimental). Finally, unprecedented achievement of high magnetization (∼0.6 T) and ultra-high resistivity (∼10{sup 10 }μΩ cm) is shown. High magnetization comes from the preservation of the existing protective shell C, with no significant degradation on the particle net-moment, and high electrical insulation is ensured by adequate grafting of the secondary shell P{sub 1}. To conclude, the metal/polymer nanocomposites are situated in the landscape of soft ferromagnetic materials for RF applications (i.e., inductors and antennas), by means of two phase-diagrams, where they play a crucial role.

• OSTI ID: 22597006
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 9 Vol. 119; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANTENNAS
COBALT
ELECTRICAL INSULATION
ELECTRICAL PROPERTIES
FERROMAGNETIC MATERIALS
FILMS
GRAFTS
GRAPHENE
MAGNETIZATION
NANOCOMPOSITES
NICKEL
PHASE DIAGRAMS
POLYSTYRENE
POWDERS
PYRENE
SHELLS
SPIN
SPIN-ON COATING