SEPARATION OF THE THRESHOLD FIELDS FOR CHARGE-DENSITY-WAVE MOTION IN NBSE3 USING ELASTIC STRAIN

We have measured the effect of elastic strain epsilon on the threshold field E(T) of NbSe3. The minimum in E(T) versus temperature T, E(min) , doubles at epsilon almost-equal-to 1 % for the upper charge-density wave (CDW) but increases by about 10% for the lower CDW. Using a plot of E(T) versus the reduced temperature t = T/T(p)(epsilon), where T(p) (epsilon) is the Peierls transition, we show that t(min), the temperat ure where E(T) goes through a minimum, is independent of epsilon. Belo w t(min), E(T) can be separated into two additive terms, one dependent on t only, and one dependent on epsilon and t: E(T)(t, epsilon) = E(T )'(t) + E(T)''(t, epsilon). E(T)'(t) is nearly independent of impurity concentration of n(i) whereas E(T)''(epsilon, t) increases with incre asing n(i).