The spinel structure Zn 1.8 Co 0.2 TiO 4 single crystals with 5 mm diameter and 30 mm length were successfully grown by an optical floating zone method. The as-grown crystals were characterized by X-ray diffraction (XRD), Raman and X-ray photoelectron spectroscopy (XPS). Some Zn 2+ ions at tetrahedral and octahedral sites should be replaced by doped transition metal Co 2+ ions. The temperature-dependent Raman spectra of spinel Zn 1.8 Co 0.2 TiO 4 crystals were also described. The optical phonon behaviors of Zn 1.8 Co 0.2 TiO 4 are stable within the temperature range. The magnetic properties of Zn 1.8 Co 0.2 TiO 4 were investigated by using Physical Property Measurement System.