Regensburg 2002 – scientific programme
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DF: Dielektrische Festkörper
DF 8: Phasenüberg
änge und Spektroskopie
DF 8.3: Talk
Thursday, March 14, 2002, 15:50–16:10, 11
Investigation of the ferroelastic domain structure of TMCC by means of nuclear magnetic resonance spectroscopy — •Dieter Michel1, Samir Mulla-Osman1, Georg Völkel1, and Zbigniew Czapla2 — 1University of Leipzig, Faculty of Physics and Geosciences, D-04103 Leipzig, Germany — 2University of Wroclaw, Institute of Experimental Physics, PL-50204 Wroclaw, Poland
35Cl NMR, 35Cl NQR, and 14N NMR investigations on single crystals of Tetramethyl- ammonium Cadmium Chloride (CH3)4NCdCl3 (TMCC) are performed to get information about structural changes at the various phase transitions and to contribute to the interpretation of XRD structure determinations at low temperatures [1]. The NMR measurements are in particular focused to the ferroelastic phase below 118 K. Peculiarities in the domain structure have been found in our combined NMR studies. A twin domain structure is found in the ferroelastic P21/m phase of TMCC, i.e. six orientational domains are verified from the NMR rotational pattern at 115 K in contrast to the expected number of three monoclinic 1200domains for a classical 6/mF2/m transition. The rotational angle Θ between the epitaxially grown twins calculated from the strain tensors of the three Aizu orientation states to be Θ = 3.50 is in very good correspondence to the experimental result 40. Supported by the DFG and the Axel-Springer-Stiftung. [1] Peral I, Madariaga G, Perez-Etxebarria A, Breczewski T 2000 Acta Cryst. B 56 215