Fig. 7

Comparing M − H curves of the prepared samples: a NiO, Ni0.95Cr0.05O, and Ni0.95Co0.05O; b NiO, Ni0.95Cu0.05O, and Ni0.95Zn0.05O; c NiO, and Ni0.95Fe0.05O

Comparing M − H curves of the prepared samples: a NiO, Ni0.95Cr0.05O, and Ni0.95Co0.05O; b NiO, Ni0.95Cu0.05O, and Ni0.95Zn0.05O; c NiO, and Ni0.95Fe0.05O