Paramagnetic defects in irradiated ferroelectric (NH4)2SO4

Abstract
EPR studies of x‐ray damaged crystals of (NH4)2SO4 show that long lived defects, NH3+ ions, are produced in two inequivalent sites with each site having two magnetically inequivalent orientations. All sites have approximately the same isotropic hyperfine splittings which are found to be 19.0 G for nitrogen and −24.6 G for hydrogen. The anisotropic components are different for the two inequivalent sites indicating different amounts of restricted rotation for the two sites. A second transient defect is identified as SO3.