Quantum critical point in CuGeO3 doped with magnetic impurities

TL;DR

This study investigates how doping CuGeO3 with magnetic impurities like Fe and Co suppresses traditional magnetic transitions and induces quantum critical behavior characteristic of a Griffiths phase at low temperatures.

Contribution

It demonstrates that small amounts of magnetic doping lead to quantum criticality and suppress spin-Peierls and Neel transitions in CuGeO3.

Findings

Doping with 1% Fe and 2% Co damps magnetic transitions.

Quantum critical behavior appears below 30K.

Evidence of a Griffiths phase in doped CuGeO3.

Abstract

Using high frequency (up to 450 GHz) ESR and low temperature specific heat measurements we find that insertion of 1% Fe and 2% Co damps spin-Peierls and Neel transitions and for T<30K gives rise to onset of a quantum critical behaviour characteristic for a random dimer Griffiths phase.