Slow soliton motion inferred from E.P.R. measurements on Rb2 ZnCl4 : Mn2+ at T = Tc + ∈

Abstract

2014 Nous décrivons les résultats préliminaires d'une étude par R.P.E. de la phase incommensurable de Rb2ZnCl4 : Mn2+. Nous utilisons une raie de structure fine particulière pour contrôler la densité des domaines commensurables dans la phase incommensurable et pour discriminer le régime de modulation sinusoidale du régime de soliton. On observe, à Tc + 03B5, des temps d'équilibre très longs, lorsque le cristal est soumis à un saut de température.Abstract. 2014 We report preliminary results of an E.P.R. investigation on the incommensurate phase of Rb2ZnCl4 : Mn2+. We use a particular fine structure line to monitor the density of commensurate domains in the incommensurate phase and to discriminate the plane wave modulation regime from the soliton regime. Long equilibrium times are observed at Tc + 03B5, when the crystal is submitted to a thermal jump.

Reshaping of Single-Crystal Silicon Microstructures

“…Theory predicts that the soliton density n, is the order parameter which can be used to describe the IC-C transition and which goes continuously to zero on approaching T, from higher temperatures. Experimentally the behaviour of n, ( T ) has been tested by NMR (Blinc er a1 1982) and by other methods such as EPR (Pezeril and Fayet 1982) and ultrasonic measurements (Rehwald and Vonlanthen 198l), but the information about the modulation lattice usually had to be derived from signals which contain spatial averages. However, details of the real structure of the modulation lattice may play a decisive role for the critical phenomena in the vicinity of T,, and certainly they will reflect the mechanisms which lead to a spatial fixing of the modulation.…”

E.P.R. investigation of the incommensurate phase of ThBr4 : Gd3+, through fourth order spin-crystal field interaction

“…Nevertheless we assumed that this difference remained constant within a temperature range of few K around T~. 3. Tetragonal phase.…”