Proton-irradiation effect on the proton motion in TlH2PO4

We have investigated the proton-beam irradiation effect on TlH2PO4 (TDP) undergoing an antiferroelectric phase transition and a ferroelastic one. The polycrystalline sample was irradiated by a 1 MeV hydrogen ion beam to a dose of 1015 ions/cm2. The changes in the 1H nuclear magnetic resonance (NMR) line shapes are discussed in view of the two distinct proton motions, which were identified from the line shape analysis, exhibiting contrasting behaviors after the proton-irradiation.