Impact of Co-doping on the structural and magnetic properties of multiferroic CaMn7O12

In this manuscript we showed that Co-doping into CaMn7O12 (CMO) induces charge disordering between Mn3+ and Mn4+ ions into the B site in the perovskite structure leading to a cubic structure Im3¯. Both antiferromagnetic transitions at TN1 and TN2 previously observed in CMO are strongly influenced by Co-doping. The transition at TN1 disappears due to the structural disorder due to the Co doping, while that one at TN2 occurs at high temperatures. Our magnetic results explained the role of Co-doping on the magnetic ordering of CMO. Since this magnetic ordering drives the induced electric polarization in such compound, the Co doping comes up as a simple way to tune the coupling between electric polarization and magnetic helix in CMO.