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A Point Charge Model for the Ferroelectric Transition in Ammonium Sulphate
Author(s) -
Jain Y. S.,
Bist H. D.
Publication year - 1974
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.2220620132
Subject(s) - ferroelectricity , ion , phase transition , dielectric , ammonium , tetrahedron , transition point , polarization (electrochemistry) , materials science , condensed matter physics , crystal (programming language) , symmetry (geometry) , charge (physics) , point particle , crystallography , chemistry , physics , thermodynamics , quantum mechanics , organic chemistry , mathematics , geometry , optoelectronics , computer science , programming language
In ammonium sulphate the distortion of the SO 4 2− ion, which has almost tetrahedral symmetry in its paraelectric phase, occurs in a narrow region near the ferroelectric transition temperature T c = 223 °K. A point charge model has been used to compute the spontaneous polarization ( P ) due to NH 4 +and SO 4 2−ions in the crystal. The computed value of P (0.42 μC/cm 2 ) agrees well with the experimentally reported ones. The nature of phase transition has also been discussed.