Dynamic Effect of Low-Symmetric Distribution of Spins on EPR Lines in One-Dimensional Magnetic Systems. II. Enhancement by Cu Doping in TMMC

Abstract

The dynamic shift of EPR absorption line which originates from the low-symmetric spacial distribution of spins has been measured in the impure one-dimensional Heisenberg system (CH₃)₄NMn_1−xCu_xCl₃ (TMMC: Cu) with x up to 0.045 at both 9.45 GHz and 23.65 GHz. The observed shift is enhanced in its amount when Cu concentration x is increased, whereas the angular-behavior is similar to the case of pure TMMC. These results can be explained by the reduction of decay-rate of spin correlation function. Analysis of the experimental data on the basis of the diffusion model of impure chain reconfirms the validity of the theory of dynamic effect of low-symmetric spin-arrangement which has been previously proposed by present authors.