Antisite disorder-driven large electric polarization in multiferroic Nd₂CoMnO₆

The discovery of magnetism-driven ferroelectricity has recently given new hope for multiferroic devices, but very low magnetic ordering temperature as well as negligibly small electric polarization in these systems are still a challenge. Here, we report a new collinear magnetic multiferroic, ${Nd}_2$ ${CoMnO}_6$ ($T_C\sim 150$ K) with a spontaneous electric polarization, $P_S\simeq 1.3\mu$C ${cm}^{-2}$, much higher than the other known magnetic multiferroics. The high polarization value has been associated to the intrinsic $\uparrow \uparrow \downarrow \downarrow$ spin ordering-driven broken symmetry and the high degree of antisite disorder present in the system, which are confirmed through dc magnetization measurements. (paper)