Nature of Ferroelectricity in KN<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mi mathvariant="normal">O</mml:mi></mml:mrow><mml:mrow><mml:mn>3</mml:mn></mml:mrow></mml:msub></mml:mrow></mml:math>
The lattice parameters of KN${\mathrm{O}}_{3}$ were measured in the temperature region of the ferroelectric transition. The changes in the lattice parameters as the crystal unde...