Single crystal growth and magnetic properties of Co-doped ZnNb2O6

The columbite structure Zn0.9Co0.1Nb2O6 single crystals have been successfully grown by using the optical floating zone method. The as-grown crystals are characterized by X-ray diffraction (XRD), Raman spectroscopy (RS) and X-ray photoelectron spectroscopy (XPS). All these analyses show that the doping Co ions do not disturb the structure of columbite ZnNb2O6 and some Zn2+ ions are substituted by transition metal Co2+ ions without any other impurities. The magnetic properties of as-grown Zn0.9Co0.1Nb2O6 crystals have been investigated using Physical Property Measurement System (PPMS). The effective magnetic moment of Zn0.9Co0.1Nb2O6 crystals is 1.47 mu(B)/Co, indicating that Co2+ ions present in Zn0.9Co0.1Nb2O6 single crystals are in mixed HS and LS states. The ferromagnetic, antiferromagnetic and paramagnetic characters of as-grown crystals are also discussed.