Microscopic Analysis of the Surface of Potassium-Ammonium Sulfate Acid Salt Crystals

Single crystals of (K_1‒x(NH₄)_x)₃H(SO₄)₂ (x ≥ 0.57) solid solutions have been studied by electrical atomic force microscopy. At 296 K, the local current–voltage characteristics of trigonal superprotonic phases were measured for the samples with different concentrations of K and NH₄ cations as a function of the c axis orientation, and anisotropy of conductivity was established. The degree of the dependence of the conduction properties on the composition is determined. The temporal changes in the morphology, potential, and surface capacitance derivatives of the (001) (K_0.43(NH₄)_0.57)₃H(SO₄)₂ surface were traced and evaluated when the samples were held in air under conditions of constant humidity and temperature.