MEASUREMENT OF THE CHARGE-DENSITY-WAVE CORRELATION LENGTH IN NBSE3 BY HIGH-RESOLUTION X-RAY-SCATTERING

We have measured the correlation length of the q1 charge-density wave in NbSe3 using high-resolution x-ray scattering. For a heavily Ta-doped crystal having a residual resistivity ratio rR of 10, the T=77 K correlation lengths parallel and transverse to the quasi-one-dimensional b* direction are lb*0.9 m and la*0.1 m, respectively. For an undoped crystal (rR300), we obtain lower bounds lb*2.5 and la*1.9 m, the latter value being comparable to the thickness of typical crystals. These results are in excellent agreement with a recent weak-impurity-pinning analysis of finite-size effects observed in transport properties. © 1990 The American Physical Society.