Models and Magnetism in One-Dimensional Systems; Low-Temperature Magnetic Susceptibilities of Dimethylammonium Trichlorocupate (II) and Tetramethylammonium Trichloronickelate (II)

Abstract

The initial susceptibilities of powder dimethylammonium copper (II) chloride (DMACuCl₃) and tetramethylammonium nickel (II) chloride (TMANiCl₃) have been measured in the ranges 1.7–91 °K and 1.6–79 °K, respectively. DMACuCl₃ exhibited deviations from Curie‐Weiss behavior below 10 °K. The deviations were not inconsistent with models based on linear antiferromagnetic interactions. Eight models were used in an attempt to fit these deviations. A least‐squares fit of the data to the relation χ_M=C/(T+θ) − α in the Curie‐Weiss region yielded the following values: C=0.437 (0.006), θ=0.317 (0.278), and α=−0.00014 (0.00007). TMANiCl₃ exhibited deviations from Curie‐Weiss behavior below 30 °K which were not inconsistent with linear ferromagnetic interactions. Two one‐dimensional models were used to fit these deviations. A least‐squares fit of the data to the relation χ_M=C/(T+θ) − α in the Curie‐Weiss region yielded the following values: C=1.28 (0.34), θ=−4.80 (5.25), and α=0.00010 (0.00379). The differences between the data reported herein and the previously reported magnetic behavior of KCuCl₃ and CsNiCl₃ indicate the strong possibility that a dominant factor in the magnetic behavior of the latter complexes is interchain interaction.