Grain boundary (GB) doped SrTiO3 exhibits interesting electroceramic p
henomena including varistor and barrier layer capacitor behaviour. We
present here our investigation of GB acceptor-doped SrTiO3 using analy
tical electron microscopy including electron holography. Mn was diffus
ed into sintered polycrystalline SrTiO3 to attain GBs which are rich i
n Mn. The presence and spatial extent of Mn at the GBs were analysed u
sing x-ray emission spectroscopy (XES) and parallel electron energy lo
ss spectroscopy (PEELS). The valence state of Mn was determined using
PEELS to be predominantly +2. Finally, transmission high-energy electr
on holography was utilized to directly image and quantify the electros
tatic potential and associated space-charge across the GBs directly. T
he holography results reveal a negatively charged GB with positive spa
ce-charge, indicating that Mn with a valence of +2 resides as an accep
tor dopant on the Ti site at the GB core. The barrier height and local
charge density distribution, including the Debye length, of the doubl
e Schottky barrier at the GB are derived from these holography results
. This investigation demonstrates the usefulness of electron holograph
y as a bulk-sensitive technique to probe the statics and dynamics of e
lectrostatic field distribution and electrical charge across interface
s in technologically useful materials, and the need to employ diverse
analytical techniques for such an investigation.