Systematic studies on magnetism of divalent 3d transition metal ions in ordered ReO₃-type fluorides MZrF₆ (M = Ti, V, Cr, Mn, Fe, Co, Ni, and Cu)

We have investigated eight magnetic fluorides MZrF₆ (M = Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) with ordered ReO₃-type structure, which have face-centered cubic magnetic lattices, using X-ray diffraction, magnetization measurement, and heat capacity measurement. The Ni compound shows an antiferromagnetic order at T_N = 3.6 K and a spin-flop transition at 1.2 T. The other compounds show no sign of magnetic ordering down to 2 K. For each compound, temperature dependence of magnetic susceptibility and magnetization process at low temperatures are analyzed using mean-field approximation. It is revealed that the Ti and V compounds have antiferromagnetic interactions and that geometrical frustration suppresses formation of long range magnetic ordering in these compounds. In addition, Ti²⁺ with the fictitious spin state of J_eff = 2 makes the magnetic system robust against magnetic field. (author)