A neutron scattering study of the impurity effects on the one-dimensional antiferromagnet TMMC

Abstract

Quasi-elastic and inelastic neutron scattering measurements have been performed on the magnetic system (CD3)4NMn(1- x)CuxCl3 with x=0.03 and 0.08. A decrease of the one-dimensional correlation length ξ with respect to pure TMMC is observed and discussed. Low Q magnons have been studied at 4.2 K for x = 0, 0.03 and 0.08. The dynamic critical value Qc above which 1d magnons start to appear is related to the inverse correlation length κ = aξ -1/π (a is the distance between spins) by Q c ≃ 2 κ, in agreement with other measurements as a function of temperature on pure TMMC