Fig. 3.
Helicoids formed by the narrow TNE films with the thickness 35.2 μm. (A) Shape of the L-geometry ribbons: left-handed at 370 K; almost flat at 353 K; right-handed at 330 K. The ribbon width is 0.23 mm. (B) Shape of the S-geometry ribbons: right-handed at 378 K; left-handed at 334 K. The ribbon width is 0.22 mm. (C) Temperature dependence of the inverse of the twist pitch (pT). The pitches of the left- and right-handed twist are defined to be positive and negative, respectively. The open and filled symbols represent the data obtained in the cooling and heating processes, respectively; and the (red) circles and the (blue) squares represent the data of the L-geometry and those of the S-geometry, respectively. The lines represent the theoretical predictions.