Some Dielectric and Optical Properties of KD2PO4

Abstract

The Curie point of KD₂PO₄ is found to be 222°±1°K, which is 9°K higher than previously reported. It is believed that the higher value is due to more complete deuteration. Other physical properties (at room temperature unless otherwise noted) are as follows: dielectric constant from 208° to 300°K; contour shearmode resonance‐frequency constant from 270° to 320°K; elastic compliance, s₆₆^E=165±3×10⁻¹² m²/N; piezoelectric constant, d₃₆=58±2×10⁻¹² C/N; electromechanical coupling, k₃₆=0.22±0.01; optical absorption between 200 and 2600 mμ for both KD₂PO₄ and KH₂PO₄ (the transmission of a 7.4‐mm‐thick KD₂PO₄ sample was greater than 50 percent from 400 to 1850 mμ); zero stress electro‐optic coefficient, r₆₃=26.4±0.7×10⁻¹² m/V; lattice constants for both KD₂PO₄ and KH₂PO₄; and spontaneous polarization and coercive field from 150° to 222°K.