Drastic Reduction of TN in a Quasi-One-Dimensional Ising Spin System with Small Amount of Impurity Spins

Abstract

The drastic reduction of the Nèel temperature T _N has been observed by the measurement of heat capacity and magnetic susceptibility in a quasi-one-dimensional Ising spin system (CH ₃ ) ₃ NHCoCl ₃ ·2H ₂ O( T _N =4.1 K) with small amount of impurity Mn ²⁺ ions. The reduction is quite steep; T _N ( x )≤0.70 T _N (0) at x =6 ( x : atomic % of Mn ²⁺ ions). For x >6, the reduction becomes rather gradual.