Lattice location and annealing studies of Hf implanted CaF2

Hafnium ions were implanted into calcium fluoride single crystals. The lattice damage introduced by the implantation was investigated with the Rutherford backscattering (RBS) channelling technique. The lattice location of the implanted ions was determined by performing channelling measurements for the 〈1 1 0〉 crystal direction. A comparison of the angular scan with Monte Carlo simulations leads to the conclusion that >90% of the Hf ions are on Ca sites directly after implantation. Subsequent annealing of the samples was performed in a rapid thermal annealing apparatus. Perturbed angular correlation (PAC) measurements with 181Hf(181Ta) show quadrupole interactions with νQ1 = 300(3) MHz (η = 0.00), νQ2 = 1285(13) MHz (η = 0.43) and νQ3 = 1035(10) MHz (η = 0.00) after annealing up to 1200 K.