Effect of Mn doping on the 1/3 magnetization step in Ca3Co2−xMnxO6

The 1/3 magnetization step is an important feature in spin frustrated Ca3Co2O6 and can be modified by chemical doping. Taking Ca3Co2−xMnxO6 as an example, we find that as Mn-doping reaches x=0.33-0.35, the field-induced 1/3 magnetization step, which is a manifestation of the partially disordered antiferromagnetic state, tends to vanish. The critical value of x=0.33-0.35 is consistent with the composition where the paramagnetic Curie temperature changes its sign from positive to negative, showing a correlation between the 1/3 magnetization step and the magnetic exchange interaction.