Correlation between structural change and electrical transport properties of Fe-doped chrysotile nanotubes under high pressure

Fe³⁺ doped chrysotile nanotubes (NTs) have been synthesized under controlled hydrothermal conditions, and have been characteristic of layered-walls and room-temperature ferromagnetism. High-pressure in situ impedance spectra and synchrotron XRD measurements are performed on Fe-doped chrysotile NTs to reveal the electrical transport and structural properties under compression. Sample resistance (R _sum) was found to increase with the pressure elevation, accompanying the step decrease in the grain boundary relaxation frequency (f _gb), which reflects the bandgap broadening and dipoles polarization weakening due to the application of pressure. Furthermore, it is found that both R _sum and f _gb change their pressure dependences at ∼5.0 GPa, which is attributed to the nonlinear compressibility of c-axis and even the underlying lattice distortion of monoclinic structure obtained in the XRD observations. (paper)