Optical bandgap reduction and ferromagnetic enhancement at room-temperature in PbTi1-xFexO3-δ ferroelectrics

The PbTi1-xFexO3-δ (xPTFO) ferroelectric ceramics have been studied by means of structural characterizations, optical and magnetic measurements. All the samples show a tetragonal perovskite structure with uniform grains. In Fe-doped PbTiO3, the oxygen-vacancies were confirmed by an X-ray photoelectron spectroscopy, which affect the materials' optical and magnetic properties. The optical bandgap of xPTFO decreases significantly with increasing Fe content, expressed by (2.78-5.05x) eV. Magnetic measurements show a ferromagnetic-paramagnetic transition occurs in xPTFO ceramics, which can be attributed to the competition between ferromagnetic and paramagnetic/antiferromagnetic components. These findings will open up a route to design optimal perovskite compounds for photovoltaic devices and magnetic storage.