Electrical resistance of low-angle tilt grain boundaries in acceptor-doped SrTiO3 as a function of misorientation angle

The transport of charge across symmetrical low-angle [001] tilt grain boundaries in Fe-doped SrTiO3 was examined. Grain boundary resistances were obtained from impedance spectroscopy measurements on bicrystals with misorientation angles θ=2.3°, 5.4°, and 7.8° as a function of temperature and oxygen partial pressure. By comparing these data with values predicted from a double Schottky-barrier model, we show that the resistance of a low-angle tilt grain boundary in acceptor-doped SrTiO3 is correlated with its dislocation content, but in a nontrivial manner.