Peculiarity of a magnetic structure in a quasi-one-dimensional columbite Co0.4Ni0.6Nb2O6

Abstract

Quasi-one-dimensional (Q1D) spin chain systems have great potential applications in high-density information storage devices, quantum information and computers, because of their quantum magnetism properties. The low-dimensional magnetic behavior has been investigated in ANb2O6, (A = Mn, Fe, Co or Ni) compounds, the structural and magnetic properties are very interesting because the system presents weakly interacting Ising chains, which leads to this quasi-one-dimensional magnetic order. Our investigation combines specific heat and magnetic measurements; x-ray and neutron diffraction (ND). In this work, we present a Co/Ni orthorhombic structure, called columbite, which crystallizes with Pbcn space group, whose formula is Co0.4Ni0.6Nb2O6. Co for Ni substitution induces a continuous lattice volume decrease, preserving the orthorhombic crystal structure. Magnetic susceptibility and specific heat measurements reveal that antiferromagnetic order occurs at 3.4 K, as a consequence of weak interchain interactions. Partial substitution of the magnetic ion tends to change the magnetic ordering observed in the CoNb2O6 and NiNb2O6. Lastly, we present this magnetic structure changes with the Ni-Co substitution.