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Electrical and thermal studies of NaNO 2
Author(s) -
Ahmed S. A.,
Ali M. H.
Publication year - 1996
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221940209
Subject(s) - ferroelectricity , phase transition , electrical resistivity and conductivity , phase (matter) , dielectric , condensed matter physics , nano , crystallite , materials science , atmospheric temperature range , thermal , chemistry , thermodynamics , physics , optoelectronics , composite material , organic chemistry , quantum mechanics , metallurgy
The present paper reports on experimental results on polycrystalline NaNO 2 employing the dc resistivity, DTA, and unit cell parameters (measured by X‐ray diffractometry) in the temperature range from 298 to 480K. All the presented results confirm, in addition to the well‐known phase transitions at 436.5 and 438 K, the existence of a second‐order phase transition occurring at 448 K. We found clear evidences that the ferroelectric phase transition of NaNO 2 is of second order close to the first‐order one, and the rotation of the NO 2 −radical mostly takes place around the c ‐axis. The high‐temperature phase transformation occurring at 448 K is thought to be due to the completely disordered arrangement of the NO 2 −radicals in the normal paraelectric phase.