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Spin—lattice relaxation of several nuclei near the ferroelectric transitions of TGS and TGFBe
Author(s) -
Müller D.,
Petersson J.
Publication year - 1976
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.2220780118
Subject(s) - ferroelectricity , condensed matter physics , relaxation (psychology) , atmospheric temperature range , spin–lattice relaxation , materials science , phase transition , lattice (music) , transition temperature , doping , physics , thermodynamics , dielectric , psychology , social psychology , paramagnetism , superconductivity , optoelectronics , acoustics
Spin—lattice relaxation time, T 1 , measurements are reported and interpreted of the nuclei H 1 , C 13 , and N 15 in TGS and F 19 in TGFBe. In particular the behaviour of T 1 is investigated near the ferroelectric phase transition temperatures of these crystals. The ferroelectric contribution to the C 13 relaxation rate in TGS doped selectively in the CH 2 group as well as the ferroelectric contribution to the F 19 relaxation rate in TGFBe show an anomalous temperature dependence near T c which can be described by a logarithmic singularity. The ferroelectric contribution to the spin—lattice relaxation rate of the protons in TGS shows a rather complicated temperature and frequency dependence. T 1 of N 15 doped TGS is nearly constant in a wide temperature range. The presented experimental results are in accordance with the assumption of an order—disorder model for the motions of the molecular groups which cause ferroelectricity in crystals of the TGS group.