Magnetic and optical properties of Co-doped ZnO nanorod arrays Wei Wang, Fuchun Zhang, Xiaoyang Wang, Shuili Zhang, Junfeng Yan, Weibin Zhang and Weihu Zhang Eur. Phys. J. Plus, 135 1 (2020) 40 Published online: 10 January 2020 DOI: 10.1140/epjp/s13360-019-00086-z