Lattice sites of Cd in ferroelectric BaTiO$_3$

The radioactive isotope 111mCd was implanted into BaTiO3 in order to measure electric field gradients with Perturbed Angular Correlation spectroscopy (PAC). It is possible to anneal the implantation induced lattice damage to a certain extent. Then, 111mCd probes are positioned at two sites with distinct axially symmetric electric field gradients characterized by the quadrupole coupling constants of 33.9(9) and 69.8(9) MHz. These electric field gradients can be assigned to 111mCd at the Ti- and the Ba-sites.