Mechanism of ferroelectric phase transition in ultra-dispersed sodium nitrite particles

Abstract

A mechanism of the ferroelectric phase transition in nanocomposite materials based on porous glasses with the average pore diameter of 7 nm with embedded sodium nitrite has been discussed. The results of analysis of temperature evolution of structure, thermal vibrations of ions, and interatomic distances are presented for these nanocomposites. It is shown that the thermal vibrations play the important role in a modification of ferroelectric phase transition from the first order, characterizing bulk compound, to the second order in ultra-dispersed sodium nitrite nanoparticles.

Keywords:

• Ferroelectric nanocomposites
• sodium nitrite
• phase transition
• size effect
• porous glasses

Acknowledgment

S. B. Vakhrushev thanks the Russian Foundation for Basic Research – BRICS, grant 19-52-80019. Yu. A. Kumzerov thanks the Russian Foundation for Basic Research, grant 19-02-00760.