Enhanced electromagnon excitations in Nd-doped BiFeO3 nanoparticles near morphotropic phase boundaries

In multiferroics, the electromagnons have been recognized as a noticeable topic due to its indispensable role in magnetoelectric, magnetodielectric, and magnetocapacitance effects. Here, the electromagnons of Bi1-xNdxFeO3 (x=0~0.2) nanoparticles are studied by terahertz time-domain spectroscopy, and the impacts of doping concentrations on electromagnons are discussed. We found that the electromagnons in the Bi1-xNdxFeO3 are associated with their phase transition. The total coupling weight of electromagnons is gradually increased at polar R3c structures and then come down at antipolar Pbam phase, and the weight at antipolar phase is less than that of pure R3c phase. Interestingly, a colossal electromagnon is observed at the polar-antipolar and antiferromagnetic-ferromagnetic phase boundaries. Our work offers an avenue for designing and choosing materials with better performances of magnetodielectric and magnetocapacitance.