非磁性強誘電体PBTIO₃中の転位芯による一次元原子スケール・マルチフェロイクス

抄録

Atomically thin multiferroics with the coexistence and cross-coupling of ferroelectric and (anti-)ferromagnetic order parameters are promising for novel magnetoelectric nanodevices. However, such ferroic order disappears at a critical thickness in nanoscale. Here, we develop a new route to ultrathin multiferroics by engineering edge dislocation cores in nonmagnetic ferroelectric PbTiO3. We demonstrate from first principles that the nonstoichiometry intrinsic to the dislocation cores unexpectedly brings about magnetism with a localized spin moment around the core. This magnetism interacts with polarization directions through ferromagnetic-antiferromagnetic-nonmagnetic phase transitions, i.e., nonlinear magnetoelectric effect. This work therefore shows that the edge dislocations can act as an atomically thin multiferroics.