Linear and Volume Thermal Expansions of Ferroelectric NaNO 2

The linear thermal expansions x i ( i = a, b, c ) of ferroelectric NaNO 2 single crystals were measured by means of a clip-type dilatometer using four strain gauge elements below 460 K down to liquid helium temperature. In this work, the coefficients f i ( i = a, b, c ) of linear thermal expansions showed anomalies at the Curie temperatures T C = 437.6 K and the Néel temperature T N = 438.8 K on heating. The coefficient g of volume thermal expansion showed the clear u -type anomaly around the T N and the sharp peaks around the T C . In the latter case the g changed complicatedly.

Keywords:

• Nano 2
• Ferroelectricity
• Thermal Expansion
• Strain Gauge