Apparently enhanced magnetization of Cu(I)-modified γ-Fe2O3 based nanoparticles Xiaoyan Qiu, Zhenghong He, Hong Mao, Ting Zhang, Yueqiang Lin, Xiaodong Liu, Decai Li, Xiangshen Meng and Jian Li Eur. Phys. J. B, 90 11 (2017) 227 Published online: 20 November 2017 DOI: 10.1140/epjb/e2017-80264-7