The magnetic bahavior of the isomorphous compounds [Cr(NH3)6][Cr(CN)6] and [Cr(H2O)(NH3)5][Cr(CN)6] has been studied by means of zero-field susceptibility measurements. The materials order ferromagnetically at 0.60 and 0.38K, respectively. The compounds behave as examples of the ferromagnetic (S=3/2) Heisenberg body-center-cubic lattice. The susceptibilities have been analyzed and compared to the Padé approximants of the high-temperature series expansion for this model, a remarkably good fit being obtained with exchange constants 0.042 and 0.022 K, respectively. Another bimetallic substance, trans-[Cr(en)2(H2O)2]trans-[Cr(en)2(OH)F]2(CIO4)5·2H2O, with a dominant Heisenberg ferromagnetic interaction J/kB=0.122 K in one dimension, orders antiferromagnetically at 0.14 K due to a weaker interchain interaction with exchange constant z′J′/kB=-0.019 K. The three sets of measurements have been carried out on powdered samples for which demagnetization effects are important. The exchange interactions are remarkably weak for such concentrated magnetic materials, yet they are stronger than those found in a number of other such Cr/Cr compounds. © 1985.
|Publication status||Published - 1 Jan 1985|