Freestanding Individual Single-walled Carbon Nanotube Synthesis Based on Plasma Sheath Effects

Abstract

Polarized neutron diffraction provides information about the magnetization density of each individual crystallographic site. In the present paper the role of the atomic site susceptibility tensor χ i j accounting for the magnetic response of individual atoms to an external magnetic field is discussed. The symmetry of this tensor is very similar to that of the tensor u i j describing the thermal motion of atoms. By analogy with the atomic displacement parameters (ADPs), atomic susceptibility parameters (ASPs) can be introduced.The six independent ASPs can be determined from polarized neutron flipping ratio measurements and visualized as magnetic ellipsoids which are analogous to the thermal ellipsoids obtained from ADPs. If the local anisotropy is small, these magnetic ellipsoids approximate to spheres with diameters proportional to the induced magnetization. In other cases, anomalous (elongated or flattened) ellipsoids will occur. The ASPs have been determined for the compound Nd 3−x S 4 which has the Th 3 P 4 structure. They correspond to strongly oblate magnetic ellipsoids; in contrast, in the isomorphous compound Sm 3 Te 4 the magnetic ellipsoids are found to be prolate.

Formation of Freestanding Single‐Walled Carbon Nanotubes by Plasma‐Enhanced CVD

“…The detailed catalyst preparation is described elsewhere. [28] The TEM observation brings direct information about the situation that SWNTs are grown from the catalyst supported by zeolite (for the TEM observation, zeolite powders after plasma irradiation are dispersed in ethanol with ultrasonication for 15 min). This is the first result in a sense that SWNTs can be grown even using PECVD.…”

“…9b). Detailed experimental conditions, and catalyst preparation are described elsewhere [21,22,28]. A diffusion plasma was formed by a capacitively-coupled, planer-type discharge as shown in Figure 9c [38].…”

Growth of Single-Walled Carbon Nanotubes by Plasma CVD

“…Since the diffusion region in plasma is known to have very low electron temperatures, we used the diffusion plasma to decrease the energy of ions attacking the catalyst to below a few eV. SWNT growth under the diffusion plasma region occurs on a flat substrate without using catalyst support materials [21][22][23]. Thus, the critical element promoting catalyst aggregation is high-energy ion bombardment.…”

Carbon Nanotube Synthesis in Atmospheric Pressure Glow Discharge: A Review

“…Substrates were located in the plasma chamber at an appropriate distance from the bulk plasma so that direct exposure of the substrates to the energetic ions was avoided. Ion bombardment destroyed the nanostructured zeolite; only MWCNTs were synthesized in the tip growth regime when the substrates were exposed directly to the plasma 37. They also synthesized free‐standing SWCNTs using an electric field working on the substrate while optimizing ion flux and ion energy simultaneously 37, 38.…”

“…Ion bombardment destroyed the nanostructured zeolite; only MWCNTs were synthesized in the tip growth regime when the substrates were exposed directly to the plasma 37. They also synthesized free‐standing SWCNTs using an electric field working on the substrate while optimizing ion flux and ion energy simultaneously 37, 38. More recently, Kawarada and co‐workers developed a unique plasma process called point‐arc microwave plasma (PA‐MP) CVD 39, 40.…”