The growing studies of potassium dihydrogen phosphate (KDP) crystals have been the interest of researchers thanks not only to their unique nonlinear optical, dielectric and ferroelectric properties, but also to their varied uses as electro-optic modulators, harmonic and parametric generators. In the process, the framework of this thesis has allowed us to make a chemical preparations of single crystals by use a partial substitution technical of phosphorus by arsenate in new compounds derive from the KDP family. On the one hand, the presence of interesting physical properties specific to NDAP material provided new results compared with the compounds studied in the KDP family, in particular the presence of superconductivity at room temperature. This last point seems promising for the application of this material in various technological fields. On the other hand, the considerable improvement of the physical properties of KDP doubly substituted ( KNDAP ), it offering new perspectives for military and fundamental applications.
