Dielectric and neutron diffraction studies of radiation damage on modulated deuterated thiourea [SC(ND2)2]

In order to demonstrate the effect of x-radiation damage on a typical modulated insulator, dielectric susceptibility and neutron diffraction measurements were performed on previously irradiated specimens of deuterated thiourea [SC(${\mathrm{ND}}_2$ ${)}_2$]. With increasing irradiation dose, an enhancement of hysteresis and memory effects is observed, together with a smearing out of the lock-in phases of order 9 and 8. Neutron measurements of the modulation wave vector δ${\mathrm{b}}^{\mathrm{*}}$ give evidence for the existence of quasiplateaus in the δ(T) curve for irradiated samples. The connection between the present findings and results from a previous x-ray study on SC(${\mathrm{ND}}_2$ ${)}_2$ in an applied electric field is discussed.