[58] Four-States Multiferroic Memory Embodied Using Mn-Doped BaTiO₃ Nanorods

Multiferroics that show simultaneous ferroic responses have received a great deal of attention by virtue of their potential for enabling new device paradigms. Here, we demonstrate a high-density four-states multiferroic memory using vertically aligned Mn-doped BaTiO₃ nanorods prepared by applying the dip-pen nanolithography technique. In the present nanorods array, the polarization (P) switching by an external electric field does not influence the magnetization (M) of the nanorod owing to a negligible degree of the P–M cross-coupling. Similarly, the magnetic-field-induced M switching is unaffected by the ferroelectric polarization. On the basis of these, we are able to implement a four-states nonvolatile multiferroic memory, namely, (+P,+M), (+P,–M) ,(−P,+M), and (−P,–M) with the reliability in the P and M switching. Thus, the present work makes an important step toward the practical realization of multistate ferroic memories.