Dielectric, NMR and X-ray diffraction study of pseudo-one-dimensional Cs1-x(NH4)(x)H2PO4

Mixed crystals Cs1-x(NH4)(x)H2PO4 of the ferroelectric CsH2PO4 (CDP) and th e antiferroelectric NH4H2PO4 were grown with x = 0.2 (CADP0.2) in solution. The structural properties of the crystal were analyzed by means of X-ray d iffraction. Dielectric measurements at several temperatures and frequencies have been performed along the three crystallographic axes in this sample a nd also in the fully deuterated CADP0.2 sample (DCADP0.2). Dielectric and N MR experiments in a powdered sample were also performed. The shift of the t ransition temperature as a function of x and deuteration, and the changes i n the properties of the different phases together with, the thermally-activ ated conductivity found in the paraelectric phase will be discussed and rel ated with the several relaxation mechanisms measured in the NMR experiments .