A Study of the Incommensurate Phase of Rb₂ZnCl₄by ESR

Abstract

The ESR absorption spectrum of Mn 2+ ions at Zn positions has been studied in the incommensurate phase of Rb 2 ZnCl 4 . It is known that Rb 2 ZnCl 4 crystals exhibit an incommensurate phase between temperatures T i = 303 K and T l = 192 K. The form and the temperature dependence of ESR spectra are in good agreement with the predictions of the phase soliton theory. The parameters h 1 and h 2 determining the magnetic resonance field show, as expected, a power law as a function of the temperature. A modified superposition model was used to estimate the modulation amplitude of the incommensurate phase, and the principal axis of the zero field splitting D.

Modulated structure ofRb2ZnCl4in the soliton regime close to the lock-in phase transition

“…Unfortunately this error seems to be propagating in more recent publications. 26 The effect of a soliton regime on the diffraction diagram of Rb 2 ZnCl 4 was analyzed theoretically and simulated by Aramburu et al 27 It was shown that, if the effect of secondary modes is neglected, the ratio of the intensities of pairs of fifth-order and first-order satellites superimposing at the lock-in transition will follow a unique law, dependent only on the soliton density n s and independent of the specific reflection. A simulation showed that secondary modulations not associated with the order parameter may produce a significant dispersion of these intensity ratios, but their mean value did not change and could still be related with the theoretical value dependent only on n s .…”