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Lipid-Modulated Assembly of Magnetized Iron-Filled Carbon Nanotubes in Millimeter-Scale Structures

“…However, it should be noted that this ''pre-magnetization'' step is not expected to impart the entire nanotube population with a well-defined magnetic dipole moment, because not all the tubes are completely filled with Fe, and not all the iron atoms are present in the ferromagnetic -Fe configuration. 18,[21][22][23][24][25] Droplet drying of pre-magnetized uncoated nanotubes in the absence and presence of an external magnetic field (data not shown) gave rise to similar deposition patterns as those shown in Figs. 2(a) and 2(c) for non-magnetized nanotubes, suggesting that inter-tube dipolar interactions are dominated by the (van der Waals) forces that drive aggregation of uncoated CNTs.…”

Recent developments in inorganically filled carbon nanotubes: successes and challenges

“…Ruskov et al showed that in such encapsulated CNTs, the top of the Fe core consisted of γ -Fe, α-Fe and Fe 3 C occurring sequentially along the nanowire axis [32,33]. In another study, Marco et al showed the concentric distribution of these three phases, where the innermost α-Fe core is surrounded by a γ -Fe layer and then by a Fe 3 C layer near the CNT interface [34]. Cu nanowires encapsulated in CNT can be obtained by doping Cu catalyst with alkali metals during the CVD synthesis of CNTs.…”

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

“…These structures can indeed exhibit extremely large coercivities of 0. 16 Further advancement in the synthesis of these filled-CNT structure films was achieved by with the fabrication of MWCNTsflower structures completely filled with α-Fe 7 . Continuous α-Fe filling was also reported recently in 2015 by Peci et al for the case of vertically aligned CNT films grown with a temperature-gradient driven CVD method at low vapour flow rates 20 .…”

“…Numerous research groups also reported the synthesis of large quantities of α-Fe and Fe 3 C together with γ-Fe inside MWCNTs [11][12][13][14][15] , showing the possibility of applications such as magnetic data recording and exchange bias systems 1,12,15,16 . Magnetic data recording and exchange bias are an important application for filled-MWCNT systems containing: 1) one ferromagnetic component in which the magnetic contribution is dominated by either a) Electronic mail: f.boi@scu.edu.cn b) Electronic mail: m.willis@scu.edu.cn c) Electronic mail: gxiang@scu.edu.cn large uniaxial shape anisotropy 6,9,10 or/and large magnetrocrystalline anisotropy [12][13][14]17 or 2) one ferromagnetic component magnetically coupled with an antiferromagnetic component that induces a shift in the observed hysteresis loop (exchange bias) [14][15][16] . In a typical magnetic data recording system, data densities higher than 66 Gigabit/inch 2 could be reached by recording one bit in each Fe-filled nanotube 1 .…”

“…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.…”