Journal ArticleDOI
Direct current conduction in ammonium and potassium dihydrogen phosphate
L. B. Harris,G. J. Vella +1 more
TLDR
In this article, the enthalpy of defect migration in KDP and ADP was shown to be 0.53 eV and 0.46 eV, respectively, in both cases.Abstract:
Experiment, plus critical discussion of previous work, suggests the following. Conductivity is primarily due to the migration of L defects (proton vacancies), the enthalpy for L‐defect mobility being 0.53 eV in KDP and 0.46 eV in ADP. Such L defects are produced by impurities, but there is an additional tendency towards incipient decomposition in both crystals. This leads to a high‐temperature conductivity which, in KDP, is associated with the formation of water molecules and the thermal generation of L defects and, in ADP, with the formation of ammonia molecules and the thermal generation of proton vacancies in the ammonium lattice (A defects). The enthalpy of L‐defect formation in KDP is 0.46 eV; that for A‐defect formation in ADP is 0.19 eV. Previously reported overheating effects are spurious. The conductivity is independent of field.read more
Citations
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Journal ArticleDOI
Growth and electrical characterization of L‐arginine added KDP and ADP single crystals
M. Meena,C.K. Mahadevan +1 more
TL;DR: In this paper, the authors show that L-arginine addition leads to reduction of electrical parameters of KDP and ADP single crystals which can be attributed mainly to the decrease of L-defects due to creation of additional hydrogen bonds by the impurity in random directions.
Journal ArticleDOI
Hidden nature of the high-temperature phase transitions in crystals of KH2PO4-TYPE : Is it a physical change ?
TL;DR: In this article, it is suggested that the nomenclature high-temperature phase transition (HTPT) around T p should be replaced by that onset of partial polymerization at reaction sites distributed on the surface of solids.
Journal ArticleDOI
Impedance spectroscopy and dielectric analysis in KH2PO4 single crystal
TL;DR: In this article, the activation energy of migration is 1.02 eV in the temperature range between 150 and 179 eV and 2.94 eV at temperatures above 186 eV.
Journal ArticleDOI
On the high-temperature phase transitions of CsH2PO4: A polymorphic transition? A transition to a superprotonic conducting phase?
TL;DR: In this paper, X-ray diffraction, TGA, differential scanning calorimetric (DSC), and impedance analysis were used to study the reported high-temperature phase transitions at 107, 149, 230, and 256 °C in crystals of cesium dihydrogen phosphate, CsH2PO4 (CDP).
Journal ArticleDOI
On the reported high-temperature phase transition in KH2PO4—strong evidence of partial polymerization instead of a structural phase transition
TL;DR: In this article, X-ray diffraction and thermogravimetric analysis were used to study the kinetic process of dehydration and the high-temperature phase transition (HTPT) at Tp = 453 ± 10 K in KH2PO4.
References
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Journal ArticleDOI
Electrical conductivity in NH4Cl and ND4Cl single crystals
Robert G. Fuller,F.W. Patten +1 more
TL;DR: In this article, the authors conclude that conductivity in ammonium chloride is due to the formation of either cation or anion vacancies and a subsequent process controlled by a proton transfer.
Journal ArticleDOI
Electrostatic energies in ice and the formation of defects
Journal ArticleDOI
Simple coulometer for studying protonic conduction in crystals.
TL;DR: In this paper, a simple glass coulometer with mercury electrodes was designed to measure the amount of gas evolved upon passing current through single crystals, to determine the extent to which electrical conduction in these crystals is due to protons or other gas-forming ions.