Electrical Conductivity in the KDP, ADP, and K1-x(NH4)xH2PO4 Crystals

Impedance Spectroscopy was performed to examine the electrical conductivity on KH2 PO4 KDP, (NH4) H-2 PO4 ADP and K1-x (NH4) x H-2 PO4 (x = 0.076, 0.118, 0.357, 0.857, 0.942) crystals with increasing temperature. They were grown by solvent evaporation method. Zview simulation software was used to theoretically fit electrical conductivity results as a function of frequency (1-10(6) Hz) and temperature (20-160 degrees C) with equivalent circuits. These dielectric-type materials become ionic conductors upon heating. Proton jumps in hydrogen bonds, heavier ions migration (K+ and NH4+), and rotation and reorientation of ammonium groups contributed to electrical conduction. This conduction behavior follows the Arrhenius equation with which the activation energies were determined at different temperature ranges. For ADP-rich (x > 0.8) and pure ADP crystals the conductivities are higher than those for KDP-rich (x < 0.2) and pure KDP. Lattice defects may reduce electrical conductivities in the crystals with intermediate x composition. Complex permittivity ac and complex conductivity ac were also obtained for these crystals.