Theoretical search of possible applications in RDP-ADP mixed crystals

For the search of relaxor ferroelectrics, we have investigated the boundary region between ferroelectric and glassy phases in ferroelectric-antiferroelectric mixed crystals Rb/sub 1-x/(NH/sub 4/)/sub x/H/sub 2/PO/sub 4/. From the theoretical calculation, we propose the existence of superlattice structure in a k/sub x/-direction rather than ferroelectric relaxor when the ferroelectric phase disappears with increasing x.