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Dynamic nuclear polarization in TCNQ salts
Author(s) -
Alizon J.,
Berthet G.,
Blanc J. P.,
Gallice J.,
Robert H.,
Fabre J. M.,
Giral L.
Publication year - 1978
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2220850224
Subject(s) - chemistry , tetracyanoquinodimethane , relaxation (psychology) , crystallography , analytical chemistry (journal) , molecule , psychology , social psychology , organic chemistry , chromatography
Temperature dependence of the dynamic nuclear polarization enhancement A L of the protons in tetrathiafulvalinium‐tetracyanoquinodimethan salt (TTF‐TCNQ) and potassium‐TCNQ salt is reported. In TTF‐TCNQ, A L is temperature‐independent in the range 150 to 300 K; in K‐TCNQ, A L is strongly temperature‐dependent. These results, and the knowledge of the frequency dependence of the relaxation time T 1 of the protons allow to determine the cut‐off frequency v C of the ld diffusion mechanism with respect to the nuclear and electronic frequencies v I and v S . v C is larger than 10 GHz in TTF‐TCNQ and v C is of the order of v I in K‐TCNQ. Moreover, because of the large enhancement A L observed in K‐TCNQ, the T 1 anisotropy is determined on single crystals.