Disorder-driven quantum critical behaviour in CuGeO 3 doped with magnetic impurity

Abstract

For the CuGeO 3 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.