The possible origin of ferromagnetism in PbTiO3 containing vacancies was investigated by performing first-principles calculations. It was demonstrated that O and Ti vacancies both induce ferromagnetism but by different mechanisms: the ferromagnetism driven by the O vacancy originates from the spin-polarized eg state of the nearest Ti atom, whereas that driven by the Ti vacancy was due to the half-metallic px state of the nearest O atom. The results presented here provide fundamental insights into the design of multiferroics in conventional ferroelectrics.

Vacancy-Driven Ferromagnetism in Ferroelectric PbTiO3. T.Shimada, Y.Uratani, T.Kitamura: Applied Physics Letters, 2012, 100[16], 162901