Ion beam irradiation of ABO 4 compounds with the fergusonite, monazite, scheelite, and zircon structures

The effects of irradiation on CaWO 4 , SrWO 4 , BaWO 4 , YVO 4 , LaVO 4 , YNbO 4 , and LaNbO 4 were investigated on thin crystals using 1.0 MeV Kr ions at 50‐1000 K. All of the ABO 4 compounds can be amorphized with calculated damage cross sections ( σ a  = 1/ F c0 ) in the range of ~0.30‐1.09 × 10 ‐14 cm 2 ion −1 at zero Kelvin. The analysis of fluence‐temperature data returned critical temperatures for amorphization ( T c ) of 311 ± 1, 358 ± 90, 325 ± 19, 415 ± 17, 541 ± 6, 636 ± 26, and 1012 ± 1 K, respectively, for the compounds listed above. Compared with previous in situ irradiation of ABO 4 orthophosphate samples using 0.8 MeV Kr ions, the T c values of LaVO 4 and YVO 4 are higher than those of LaPO 4 and YPO 4 by 82 K and 124 K, respectively. The T c values of the three scheelite structures, CaWO 4 , SrWO 4 , and BaWO 4 , indicate that they are the most radiation tolerant compounds under these conditions. The A‐B cation anti‐site energies, E f AB , determined by DFT range from 2.48 to 10.58 eV and are highly correlated with the A‐B cation ionic radius ratio, r A / r B , but are not correlated with T c across the different structure types, suggesting that the formation and migration energies of Frenkel defects play a more important role in damage recovery in these compounds. We also discuss the role of cation and anion charge/iconicity as determined by DFT. ABO 4 compounds with the zircon structure and B = P or V have a distinct advantage over those with B = Si as the damaged regions do not appear to be significantly affected by polymerization of (PO 4 ) 3− or (VO 4 ) 3− groups which might stabilize the amorphous fraction and ultimately lead to phase separation as observed in zircon (ZrSiO 4 ).