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The temperature dependence of the optical nonlinear susceptibility of sodium nitrite
Author(s) -
Vogt H.,
Happ H.
Publication year - 1971
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.2220440122
Subject(s) - ferroelectricity , ion , sodium nitrite , condensed matter physics , nonlinear optical , polarization (electrochemistry) , phase transition , nonlinear system , materials science , sodium , chemistry , order (exchange) , physics , dielectric , quantum mechanics , optoelectronics , organic chemistry , finance , economics , metallurgy
Information about the order‐disorder transition of NaNO 2 is obtained from the temperature dependence of the optical nonlinear susceptibility χ (2) . The decrease of χ (2) ( T ) in the ferroelectric phase can be related to increasing rotational motion of the NO 2 − ‐ions. While χ (2) indicates the degree of order within the NO 2 − ‐sublattice, the spontaneous polarization P s may be regarded as an order parameter of the Na + ‐sublattice. The difference between P s ( T ) and χ (2) ( T ) is explained by a different order‐disorder behaviour of the Na + ‐and the NO 2 − ‐ions.