TDPAC study of Fe-implanted titanium dioxide thin films

Fe-doping in TiO$_{2}$ has been proven to improve several of its properties, including the photocatalytic activity. Time-differential perturbed angular correlation (TDPAC) as the applied spectroscopy method is particularly interesting because it can probe the electric and magnetic interactions on a local atomic scale. In this work the hyperfine interactions on $^{111}$Cd atoms substituting Ti atoms in TiO$_{2}$ due to nearby Fe atoms also diluted within the TiO$_{2}$ lattice were measured as a function of temperature. The results review two fractions with distinct quadrupole interaction parameters. One site, occupied by the $^{111}$Cd probes, presents the smaller quadrupole interaction frequency, namely $\upsilon_{q1}$ = 45 MHz, and can be ascribed to sites that are more distant from the Fe substitutional site whereas the second site characterized with $\upsilon_{q2}$ = 62 MHz is related to Cd probe atoms that are closer to the Fe defect. Additionally, the system has been characterized using electron dispersive spectroscopy.