High-Field Magnetization of One-Dimensional S=1/2 Trimer System 3CuCl₂· 2dioxane

Abstract

The high-field magnetization process of a one-dimensional S=1/2 trimer system, 3CuCl₂· 2dioxane, is studied on powder samples using a pulse magnet up to 30, T between 1.5, K and 9, K. The magnetization increases nonlinearly and saturates around 15, T, characteristic of low-dimensional Heisenberg antiferromagnets. The magnetization data are consistent with a previously proposed model in which ferromagnetic trimers composed of three S=1/2 spins are weakly coupled antiferromagnetically to form a S=3/2 antiferromagnetic chain. Based on this model, the antiferromagnetic intertrimer interaction is directly derived as J_AF=-16.2, K. However, the observed magnetization curve suggests that a composite spin system consisting of three S=1/2 spins has more of a quantum nature than does a genuine S=3/2 system, because the ferromagnetic intratrimer interaction is not sufficiently strong.