Ferroelectricity and protonic conductivity in Cs1-x(NH4)xH2PO4

Mixed crystals Cs1-x(NH4)(x)H2PO4 Of the ferroelectric CsH2PO4 (CDP) and the antiferroelectric (NH4)H2PO4 were grown with x = 0.2 (CADP0.2) in solution. The structural properties of the crystal were analyzed by means of x-ray diffraction. Dielectric measurements at several temperatures and frequencies have been performed along the three crystallographic axes in this sample and also in the fully deuterated CADP0.2 sample (DCADP0.2). Dielectric and NMR experiments in a powdered sample were also performed. The shift of the transition temperature as a function of x and deuteration, and the changes in the properties of the different phases together with the conductivity found in the paraelectric phase will be discussed.