Calorimetric and dielectric studies of ferroelectric sodium nitrite confined in a nanoscale porous glass matrix.

Heat-capacity measurements of the sodium nitrite confined in a nanoscale porous glass matrix show that the intermediate incommensurate phase, present in the bulk, has disappeared and that the first-order ferroelectric transition becomes suppressed and gradual. The ferroelectric transition temperature is shifted considerably to lower temperatures. Two noncritical dielectric modes were observed; however, the observed giant growth of the dielectric constant on heating through the transition temperature TC is shown to be mainly due to the electrode polarization effect.