Browsing by Author "Zidansek, Aleksander"

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Dielectric, NMR and X-ray diffraction study of Cs1-x(NH4)xH2PO4
(1998) Meschia, S. C.; Lanceros-Mendez, S.; Zidansek, Aleksander; Schmidt, V. Hugo; Larson, R.
Mixed crystals Cs1−x(NH4)xH2PO4 of the ferroelectric CsH2PO4 (CDP) and the antiferroelectric (NH4)H2PO4 were grown with x=0.2 (CADP0.2) in solution. The structural properties of the crystal were analyzed by means of x-ray diﬀraction. Dielectric measurements at several temperatures and frequencies have been performed along the three crystallographic axes in this sample and also in the fully deuterated CADP0.2 sample (DCADP0.2). NMR experiments were also performed.
Dielectric, NMR and x-ray diffraction study of pseudo-one-dimensional Cs1-x(NH4)xH2PO4
(1999) Meschia, S. C.; Lanceros-Mendez, S.; Zidansek, Aleksander; Schmidt, V. Hugo; Larsen, R.
Mixed crystals Cs1−x (NH4) x H2PO4 of the ferroelectric CsH2PO4 (CDP) and the antiferroelectric NH4H2PO4 were grown with x = 0.2 (CADP0.2) in solution. The structural properties of the crystal were analyzed by means of X-ray diffraction. Dielectric measurements at several temperatures and frequencies have been performed along the three crystallographic axes in this sample and also in the fully deuterated CADP0.2 sample (DCADP0.2). Dielectric and NMR experiments in a powdered sample were also performed. The shift of the transition temperature as a function of x and deuteration, and the changes in the properties of the different phases together with, the thermally-activated conductivity found in the paraelectric phase will be discussed and related with the several relaxation mechanisms measured in the NMR experiments.
NMR spin-lattice relaxation study of Cs1‑x(NH4)xH2PO4
(1997) Meschia, Steven C. L.; Zidansek, Aleksander; Brandt, Dan; Schmidt, V. Hugo
Spin-lattice relaxation time T1 for 31P was measured as a function of temperature at 28.2 MHz in a powder sample of Cs1-x (NH4) x H2PO4 (CADP) crystallized from a solution with a molar ratio x = 0.2. This crystal has the same structure as CsH2PO4 (CDP), which exhibits a low-temperature pseudo-one-dimensional ferroelectric phase transition at 159 K and a superionic transition at 504 K on heating. The measured temperature dependence is explained in terms of hydrogen bond dynamics.