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Critical behavior of KDCO 3 from 2 H and 39 K single crystal NMR
Author(s) -
Odin Christophe
Publication year - 2008
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.2112
Subject(s) - chemistry , phase transition , critical exponent , zeeman effect , relaxation (psychology) , condensed matter physics , tricritical point , exponent , critical point (mathematics) , phase (matter) , transition point , logarithm , thermodynamics , physics , phase diagram , magnetic field , quantum mechanics , psychology , social psychology , mathematical analysis , linguistics , philosophy , mathematics , organic chemistry
Abstract Potassium hydrogenocarbonate KDCO 3 presents an order/disorder phase transition at T c ≈ 353 K. The critical behavior of this phase transition was studied by single crystal 2 H and 39 K NMR. The evolution of the order parameter as a function of temperature is quantified, and the critical exponent was determined, indicating a transition close to a tricritical point. The 2 H Zeeman relaxation rate is strongly increased near the transition temperature. By calculating the noncritical contribution to the Zeeman relaxation rate, we show that the observed relaxation rate clearly presents a pseudo‐divergent behavior near T c , with a logarithmic singularity. The nature of the phase transition is discussed in the light of these results. Copyright © 2007 John Wiley & Sons, Ltd.