Investigation of grain boundary segregation in acceptor and donor doped strontium titanate

Grain boundary segregation in electronic ceramics is often responsible for dictating the grain boundary properties, which in turn dictate the macroscopic electronic properties of the material. Consequently, it is important to understand the nature of segregation phenomena in these materials. Here we present results from a combination of diverse analytical techniques used to investigate the character of grain boundary segregation in acceptor (Fe, Mn) and donor (Nb) doped strontium titanate. X-ray emission spectroscopy (XES) and electron energy loss spectroscopy (EELS) analysis consistently show segregation of both acceptor (Fe, and Mn) and donor (Nb) dopant species to the grain boundaries. Within the spatial resolution of the techniques, the segregation profiles for these dopants are found to be limited to less than 5 nm about the grain boundaries. Furthermore secondary ion mass spectroscopy shows that the segregation is ubiquitous throughout the samples, and not limited to selected grain boundaries.