Single crystals of ZnO were implanted with 0.6 x 10(16) cm(-2) and 1.2 x 10(16) cm(-2) of Co ions produced by MEVVA type implanter. Channeled Rutherford backscattering (cRBS) measurements reveal incomplete amorphisation. Thermal annealing at 800 degrees C in argon leads to a reduction of point-type defects. The channeled particle-induced X-ray emission (cPIXE) measurements show partial substitutionality of Co ions directly following implantation with further growth of substitutional occupation after annealing. Magnetic measurements reveal the presence of paramagnetic and ferromagnetic phases after implantation. The value of magnetization can be interpreted as due to defects rather than Co content. The ferromagnetic phase disappears after annealing and the paramagnetic phase grows in intensity. (C) 2014 Elsevier B.V. All rights reserved.