Effects of charge-density-wave depinning on the elastic properties of orthorhombicTaS3

The results of various vibrating-reed experiments on orthorhombic ${\mathrm{TaS}}_3$ are presented. It is found that when electric fields greater than the threshold (${\mathrm{scrE}}_T$) for charge-density-wave (CDW) depinning are applied, Young’s modulus (E) decreases slowly saturating at -ΔE/E∼1% for scrE∼10${\mathrm{scrE}}_T$. This saturation is surprisingly abrupt. At much lower fields, the modulus varies as the square root of the CDW velocity, and it is suggested that velocity fluctuations may cause the anomalies. The internal friction increases very rapidly above threshold, reaching a maximum for scrE<2${\mathrm{scrE}}_T$, and then slowly decreases. The results are discussed from the point of view of an anelastic relaxation model, and also compared to other models which have been suggested.