Microstructures associated with dielectric and magnetic properties in (1-x)BiFeO3-xBaTiO3

We have investigated microstructures associated with the magnetic and dielectric properties of multiferroic mixed-perovskite compounds of the formula (1 - x)BiFeO3-xBaTiO(3) by transmission electron microscopy (TEM) combined with conventional dielectric and magnetic measurements. TEM observation revealed that there exist complicated ferroelectric (FE) domains 20-30 nm in size in the FE phase of BiFeO3. It was also found that, in an x = 0.25 compound, a weak spontaneous magnetization appears in the FE phase at 20K. From the results of the X-ray and electron diffraction experiments, it is suggested that this weak spontaneous magnetization is closely associated with the decrease in the extent of rhombohedral distortion by a partial substitution of BaTiO3 for BiFeO3.