| The resistance of NbSe(,3) and TaS(,3) fibers has been measured as a function of stress with temperature as a parameter. The elastic stress was applied along the fiber axis, up to 3 GPa for NbSe(,3) and 4 GPa for TaS(,3). The charge-density wave (CDW) transition in NbSe(,3) at 142 K has been found to shift reversibly to lower temperatures by -3.2 (+OR-) 0.4 K/GPa with little change in the resistance magnitude. The 59 K CDW transition in NbSe(,3) shifted slightly lower by -0.4 (+OR-) 0.1 K/GPa with nearly 50% increase in magnitude and was also reversible. In TaS(,3) the 222 K CDW transition was found to shift reversibly to lower temperatures by -15 (+OR-) 1 K/GPa. The stress dependence of the activation energy of TaS(,3) was found to be (TURN)24 meV/GPa. A stress-dependent anomaly, which may be interpreted as another CDW, has been observed in TaS(,3) at (TURN) 1/2% strain. A history-dependent stress effect has also been observed in TaS(,3) that appears to be superheating. The anomaly and history-dependent effect both occur over the same temperature range where thermal hysteresis was observed. Comparison is made with results obtained from pressure experiments, and interpretation of the behavior of the CDW transitions is made in terms of phase transitions. |
