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 χM=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 χM=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.