Nanoscale Mechanics of Carbon Nanotube Evaluated by Nanoprobe Manipulation in Transmission Electron Microscope

Abstract

We present a detailed study of the magnetic and crystal-field properties of the hexagonal Kondo lattice YbCu 3 Al 2 , using 170 Yb Mössbauer spectroscopy in the temperature range 0.1 K-50 K. L III -edge x-ray absorption spectra at 10 K and 300 K were also obtained; they indicate that the Yb ion is very close to trivalent over the whole temperature range. In the antiferromagnetic phase, the thermal variation of the Yb 3+ spontaneous moment has been measured and the derived transition temperature (T N = 1.95 K) is in agreement with previous specific heat and magnetic data. In the paramagnetic phase, the two components g z and g ⊥ of the g-tensor of the Yb 3+ ground crystal-field doublet have been measured. These g-values cannot be accounted for by a crystal-field-only model, and we interpret this in terms of a Kondo reduction of the paramagnetism (T > T N ) and of the spontaneous moment (T < T N ), with a Kondo temperature T K 2.3 K. In addition, the spectra in the antiferromagnetic phase show inhomogeneous broadenings due to the presence of random distortions with respect to the hexagonal Yb site symmetry, and, close to T N , dynamical effects are clearly evident and allow the Yb 3+ fluctuation frequency to be measured in the magnetically ordered phase.

Mechanical behavior of carbon nanotubes in the rippled and buckled phase

“…16 The rippling pattern itself has been studied for embedded tubes 9,18 by using transmission electron microscopy (TEM), and force measurements have also been done for tubes supported on a substrate 19,20 by using atomic force microscopy (AFM). Ideally these two methods should be combined to enable studies of freestanding structures, and early attempts have been made by using different spring elements and a) Electronic mail: krister.s@kau.se post image analysis to estimate forces 21,22 . Only recently has the use of non-optical force sensors 23 provided a true joining of AFM with regular electron microscopy instruments, and this has enabled detailed studies of the critical bending-strain for buckling and rippling in carbon nanotubes.…”

Carbon Nanotube-Based Nanomechanical Sensor: Theoretical Analysis of Mechanical and Vibrational Properties

“…By now, there are several methods to investigate the instability properties of CNTs when subjected to an axial force. The instability phenomenon of CNTs under compressive loading was observed experimentally by TEM [59][60][61][62]. Figure 14 shows the direct observation of nanotube buckling characterization by in situ transmission TEM.…”

In Situ TEM of Carbon Nanotubes

“…The authors further give an honest account of the limitations of the technique, namely, issues related to measurement of projected displacements and uncertainty of absolute force readings. The buckling mechanics of individual arc-made MWCNTs and their local plastic deformation were studied in a companion report [ 104 ]. At 200 kV (25 pA/cm 2 ), the nanotubes showed fl exibility with shape recovery on load release, but when repeatedly compressed beyond their elastic limit, structural fatigue settled in and deformation took place at the vicinity of the defects generated.…”