Paramagnetic impurity defects in LuAG:Ce thick film scintillators

ESR measurements revealed platinum impurity, which is incorporated in both pure and Ce-doped LPE films in the trivalent charge state (5d7)(5d7) at the Al octahedral sites. There are 24 magnetically inequivalent positions of the platinum ion in the lattice, which most probably originate from three static Jahn–Teller distortions at each of the eight octahedral sites per unit cell. It was found that in LuAG LPE films the Ce3+Ce3+ impurity substitutes only for Lu3+Lu3+ sites. On the other hand, at least four different structural positions of the Ce3+Ce3+ ions were clearly distinguished from measurements in the bulk LuAG crystals. Two of them correspond to the Ce3+Ce3+ at Al octahedral sites.