Crystal structures and magnetic properties of two-dimensional antiferromagnets Co_[1-x]Zn_[x]TeMoO6

Crystal structures and magnetic properties of metal telluromolybdates Co_[1-x]Zn_[x]TeMoO6 (x=0.0, 0.1, ..., 0.9) are reported. All the compounds have an orthorhombic structure with space group P2_[1]2_[1]2 and a charge configuration of M^[2+]Te^[4+]Mo^[6+]O6. In this structure, M ions form a pseudo-two-dimensional lattice in the ab plane. Their magnetic susceptibility measurements have been performed in the temperature range between 1.8 and 300K. The end member CoTeMoO6 shows a magnetic transition at 24.4 K. The transition temperature for solid solutions rapidly decreases with increasing x and this transition disappears between x=0.4 and 0.5, which is corresponding to the percolation limit for the square-planer lattice. From the magnetization, specific heat, and powder neutron diffraction measurements, it is found that the magnetic transition observed in the CoTeMoO6 is a canted antiferromagnetic ordering of Co^[2+] ions. The antiferromagnetic component of the ordered magnetic moment (3.12(3) μB at 10K) is along the b-axis. In addition, there exists a small ferromagnetic component (0.28(3) μB) along the a-axis