Low temperature magnetization of the S= 1 2 kagome antiferromagnet Zn Cu3 (OH)6 Cl2

Abstract

The dc magnetization of the unique S= 1 2 kagome antiferromagnet Herbertsmithite has been measured down to 0.1 K. No sign of spin freezing is observed in agreement with former μSR and ac-susceptibility results. The low temperature magnetic response is dominated by a defect contribution which exhibits an energy scale 1 K, likely reflecting the coupling of the defects. The defect component is saturated at low temperature by H 8 T applied magnetic fields which enables us to estimate an upper bound for the nonsaturated intrinsic kagome susceptibility at T=1.7 K. © 2007 The American Physical Society.