Electrostatic fields control grain boundary structure in SrTiO3

Functional properties of oxide ceramics are often controlled by the addition of dopant elements and the resulting alteration of oxygen vacancy concentrations within grain boundary core structures. A challenge in designing nanoscale ceramic microstructures is forming stable grain boundary networks, while minimizing unwanted impurity concentrations. In this study, it was discovered that the application of electrostatic fields during diffusion bonding of undoped SrTiO3 bicrystals leads to modifications of grain boundary core structures while misorientation angles remained unchanged. The applied electric field not only changes atomic and electronic interface structures, but also causes modifications of ensuing dielectric properties by altering local oxygen vacancy concentrations. The observations for this model system demonstrate the potential to control and modify the microscopic degrees of freedom of grain boundaries in the absence of dopant elements. Field-assisted modifications of grain boundary networks may become a disruptive technology in designing oxide microstructures for a wide range of applications.Functional properties of oxide ceramics are often controlled by the addition of dopant elements and the resulting alteration of oxygen vacancy concentrations within grain boundary core structures. A challenge in designing nanoscale ceramic microstructures is forming stable grain boundary networks, while minimizing unwanted impurity concentrations. In this study, it was discovered that the application of electrostatic fields during diffusion bonding of undoped SrTiO3 bicrystals leads to modifications of grain boundary core structures while misorientation angles remained unchanged. The applied electric field not only changes atomic and electronic interface structures, but also causes modifications of ensuing dielectric properties by altering local oxygen vacancy concentrations. The observations for this model system demonstrate the potential to control and modify the microscopic degrees of freedom of grain boundaries in the absence of dopant elements. Field-assisted modifications of grain boundary networks ...