Interplay between exchange interaction and magnetic anisotropy for iron based nanoparticles in aligned carbon nanotube arrays

Interaction of electromagnetic radiation in the 20–200 GHz frequency range with arrays of carbon nanotubes with ferromagnetic nanoparticles

“…On the other hand, the CNT-based nanocomposite can be represented as a matrix of CNTs in which ferromagnetic NPs are randomly distributed [8]. Each NP is coated by a protective shell (interface) according to the experimental findings [32,33]. We suppose that the RiLiC i contours are formed primarily due to the resistance of the CNT matrix, the NP inductance, and the capacitance of the interfaces.…”

“…The average size of the NPs is slightly less than the CNT diameter, and lies in the range of a = 20-30 nm [34], and are therefore considered as a single domain [35]. The main phase of the NPs is iron carbide (Fe3C) with an orthorhombic crystalline structure, and their saturation magnetization at room temperature is Msat ≈ 90 A·m2/kg and the Curie temperature was measured as T C = 481 K [32]. Raman spectroscopy can usually reveal slight defects in such CNTs [8,33,34].…”

“…Special attention is given to the role of the resonance resistive-inductive-capacitive (RiLiC i) circuits, which leads to a deeper understanding of the problem. Such nanocomposites can be easily synthesized in situ during the CNT growth by chemical vapor deposition, which involves carbon decomposition of an organic precursor with 3d catalytic metals such as Fe, Ni and Co [32].…”

Peeling off effects in vertically aligned Fe3C filled carbon nanotubes films grown by pyrolysis of ferrocene

“…For more than a decade films of aligned multiwall carbon nanotubes (MWCNTs) filled with ferromagnetic α-Fe and Fe 3 C have been an important subject of research owing to their attractive magnetic properties [1][2][3][4][5][6][7][8][9][10][11][12] . These structures can indeed exhibit extremely large coercivities of 0.…”

“…The high coercivities of these structures have been reported to depend strongly on crystal anisotropy, shape anisotropy, degree of alignment of the MWCNTs and exchange coupling or bias interactions 6,15,16 . The synthesis of these films is generally performed by chemical vapour deposition (CVD) of an organometallic precursor known as ferrocene on the top of thermally oxidized Si/SiO 2 substrates [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] .Commonly used fabrication methods are solid-source CVD (SSCVD) and liquidsource CVD (LSCVD) 19 . The decomposed metallocenevapour has been reported to contain Fe, H 2 , CH 4 , C 5 H 6 and other hydrocarbon species 19 that react on the substrate surface to form the metal particles from which the MWCNTs and single crystal filling will grow simultaneously.…”