Structural and Dielectric Studies of Rb0.7(NH4)0.3HSO4 in Its Paraelectric and Ferroelectic Phases

✍ Scribed by Bouattour, S. ;Ben Hassen, R. ;Kolsi, A. W. ;Jaud, J. ;Mhiri, T.

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 165 KB
• Volume: 172
• Category: Article
• ISSN: 0031-8965
• DOI: 10.1002/(sici)1521-396x(199904)172:2<491::aid-pssa491>3.0.co;2-h

✦ Synopsis

The structural phase transition of the mixed compound Rb 0X7 (NH 4 ) 0X3 HSO 4 is studied by differential scanning calorimetry and dielectric measurements. It is found that the transition occurs at 260 K to be of second order and ferro±paraelectric. The structure in the ferroelectric phase is determined at 183 K by means of single-crystal X-ray diffraction, of which the lattice constants are determined as follows: a 14X2962 # e, b 4X5873 # e, c 14X2963 # e and b 118X002 . The space group is confirmed to be P2 1 and the refined structure shows that the S±O bond lengths in the (HSO À 4 groups seem to be slightly shorter than those obtained at room temperature in the paraelectic phase.