Disorder-driven quantum critical behaviour in CuGeO3 doped with magnetic impurity

Abstract For the CuGeO3 doped with 1% of Fe, the quantum critical behaviour in a wide temperature range 1–40 K is reported. The critical exponents for susceptibility along different crystallographic axes are determined: α=0.34 (B∥a and B∥c) and α = 0.31 (B∥b). New effect of the frequency dependence of the critical exponent is discussed.