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Title: High-Temperature Phase Transitions in CsH2PO4 Under Ambient and High-Pressure Conditions: A Synchrotron X-ray Diffraction Study

To clarify the microscopic origin of the temperature-induced three-order-of-magnitude jump in the proton conductivity of CsH2PO4 (superprotonic behavior), we have investigated its crystal structure modifications within the 25-300 C temperature range under both ambient- and high-pressure conditions using synchrotron x-ray diffraction. Our high-pressure data show no indication of the thermal decomposition/polymerization at the crystal surface recently proposed as the origin of the enhanced proton conductivity. Instead, we found direct evidence that the superprotonic behavior of the title material is associated with a polymorphic structural transition to a high-temperature cubic phase. Our results are in excellent agreement with previous high-pressure ac impedance measurements.
Authors:
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Publication Date:
OSTI Identifier:
959867
Report Number(s):
BNL--82853-2009-JA
Journal ID: ISSN 0021-9606; JCPSA6; TRN: US1005815
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 127
Research Org:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org:
Doe - Office Of Science
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 43 PARTICLE ACCELERATORS; CRYSTAL STRUCTURE; IMPEDANCE; MODIFICATIONS; ORIGIN; PROTONS; SYNCHROTRONS; X-RAY DIFFRACTION; PHASE TRANSFORMATIONS national synchrotron light source