Three-dimensional polarization imaging of (Ba,Sr)TiO3:MgO composites

The dielectric tuning and loss of (Ba,Sr)TiO3:MgO bulk composites depend strongly on the connectivity and interaction among the two phases. To investigate this relationship, the polar structure and dynamics of these composites is mapped as a function of space and time using a pair of three-dimensional probes: second-harmonic confocal scanning optical microscopy (SH-CSOM), which maps ferroelectric polarization in three dimensions, and time-resolved scanning optical microscopy (TR-CSOM), which maps polarization dynamics along two spatial dimensions and one time dimension. SH-CSOM measurements reveal a high degree of homogeneity within the (Ba,Sr)TiO3 regions, while TR-CSOM measurements indicate that topologically connected regions respond with a spatially uniform phase.