Evidence of proton beam irradiation compared to isotope effect

Abstract

In this study, we obtained experimental results similar to the isotope substitution effect by using the proton irradiation of K(H0.47D0.53)2PO4 (DKDP) ferroelectric single crystals. Temperature dependence of dielectric constants showed that the ferroelectric phase to paraelectric phase transition temperature increased from 175 K to 195 K of approximately 20 K after the proton beam irradiation. It was observed that the vibration mode P(OD)2 was changed from 893 to 884 cm−1 in Raman spectroscopy. In 1H Magic Angle Spinning (MAS) Nuclear Magnetic Resonance (NMR) experiments, the isotropic chemical shift after proton irradiation decreased from 14.46 to 14.32 ppm, which is indicative of the change of the O–H…O the equilibrium distance of hydrogen bonds estimated as 1.60066 Å and 1.62228 Å before and after the proton irradiation, respectively. It was observed that the Full width at half maximum (FWHM) line width also decreased from 563 to 244 Hz in 1H MAS spectral line shape, which is indicative of obeying the displacive phase transition model.