Low-Field Remanent Magnetization in the Weak Ferromagnet Mn[N(CN)₂]₂. Evidence for Spin-Flop Behavior

Low-field dc magnetization measurements have been performed on powder samples of the weak ferromagnet Mn[N(CN) 2 ] 2 . In small dc fields, H (0.01 ≤ H ≤ 100 Oe), the zero-field and field-cooled magnetizations display the onset of a spontaneous moment below T c = 15.85(3) K, giving small magnetization values which suggest a spin-canted moment. A critical exponent, β, equal to 0.380(5) was obtained from a fit of the very low field remanent magnetization data to a power law. As the dc field is increased, the weak spontaneous magnetization continuously diminishes with respect to the total magnetization and the behavior typical of an antiferromagnet appears. When the field is increased, furthermore, a transition from the antiferromagnetic to a spin-flop state is observed.