Pseudocritical NMR frequency shift above the normal-incommensurate phase transition
Fachbereich Physik, Universität des Saarlandes, Postfach 151150, 66041 Saarbrücken, Germany
Published online: 15 April 1999
The NMR satellite frequencies were measured as a function of temperature in the normal high-temperature phase for 87Rb in Rb2ZnBr4 and Rb2ZnCl4 and for 35Cl in betaine calciumchloride dihydrate. Approaching the respective normal-incommensurate phase transition an anomalous shift of the NMR frequency is observed for the first two cases. This effect is ascribed to the increasing order parameter fluctuations. The experimental data are compared to calculations which relate the observed behaviour of the NMR frequencies to the non-classical critical behaviour of the substances under investigation.
PACS: 64.70.Rh – Commensurate-incommensurate transitions / 68.35.Rh – Phase transition and critical phenomena / 76.60.Gv – Quadrupole resonance
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 1999