Electronic and magnetic properties of carbon nanofoam produced by high-repetition-rate laser ablation

Origin of magnetic moments in carbon nanofoam

“…Our previous structural studies of the nanofoam revealed the presence of hyperbolic schwarzite layers 16,17,20 in the clusters forming the foam. Schwarzites are anticlastic ͑saddle shaped͒, warped graphitelike sheets, in contrast to the synclastic ͑ellipsoidally curved͒ sheets of fullerenes.…”

“…19 Electron diffraction of the nanofoams suggests the presence of hyperbolic "schwarzite" layers. 17,20 "Schwarzite" layers are saddle-shaped graphitic layers in which the negative Gaussian curvature arises from the presence of carbon rings larger than six members. The carbon nanofoam shows strong magnetization immediately after the synthesis, most of which is actually lost on a very short time scale immediately after the synthesis.…”

Highly conductive nanoclustered carbon:nickel films grown by pulsed laser deposition

“…The absences of hysteresis on both the doped and undoped cluster assembled films appear to support this conclusion. Various charge transport mechanisms have been proposed for amorphous carbon thin films, but a hopping mechanism wherein the conductivity is proportional to the overlap of the wavefunctions associated with adjacent hopping sites is generally considered the most probable explanation in the case of cluster-assembled films such as those reported here [7][8]. As discussed above on the basis of the evidence from Raman spectroscopy, annealing of the pure carbon thin films does not induce such a significant increase in sp 2 cluster content as might affect the transport properties.…”

“…high porosity and large surface area (3 00 -800 m 2 g -1 ) [6][7], which could make them ideal candidates for chemical sensing applications. However, sp 3 bond formation at the surface of the clusters renders them poor electrical conductors [8], making electrical detection of species very challenging. If the electrical conductivity of these cluster-assembled films could be enhanced, it would most likely increase their utility in engineering applications.…”

Diamond-Like Carbon Nanofoam from Low-Temperature Hydrothermal Carbonization of a Sucrose/Naphthalene Precursor Solution

“…Carbon nanofoams usually consist of agglomerations of porous nano-or micron-sized spheres. Such so-called nanoor micro-pearls have been produced by various methods such as laser ablation [48][49][50], chemical vapor deposition (CVD) [39,[51][52][53][54][55][56][57][58][59][60] or hydrothermal carbonization (HTC) [30][31][32][33]46,[61][62][63][64][65][66][67]. In this paper, we show that morphologies other than micropearls can be synthesized just by changing the process parameters.…”