Thermal Expansion and Dielectric Studies of the Phase Transition in Ferroelectric NaNO2at -95°C

A phase transition in ferroelectric NaNO 2 is found at -95°C from precise measurements of thermal expansion and low frequency dielectric constant. At this transition temperature, slight break exists both in dielectric constant vs. temperature and in thermal expansion vs. temperature curves. Below the transition temperature, the room temperature ferroelectric phase transforms to a high pressure phase which exists above 8 kbar at room temperature.