Change in the magnetic structure of (Bi,Sm)FeO3 thin films at the morphotropic phase boundary probed by neutron diffraction

摘要

We report on the evolution of the magnetic structure of BiFeO3 thin filmsgrown on SrTiO3 substrates as a function of Sm doping. We determined themagnetic structure using neutron diffraction. We found that as Sm increases,the magnetic structure evolves from a cycloid to a G-type antiferromagnet atthe morphotropic phase boundary, where there is a large piezoelectric responsedue to an electric-field induced structural transition. The occurrence of themagnetic structural transition at the morphotropic phase boundary offersanother route towards room temperature multiferroic devices.