Temperature range broadening of the ferroelectric phase in KNO₃ nanoparticles embedded in the pores of the nanoporous Al₂O₃ matrix

Abstract

Temperature evolution of the crystal structure and the third harmonic coefficient of potassium nitrate KNO₃ nanoparticles embedded in the pores of porous alumina oxide Al₂O₃ films with nanometer size channels has been studied. A significant expansion of the temperature range of the ferroelectric phase was found under conditions of the restricted geometry compared to the bulk material. Coexistence of the ferroelectric and paraelectric phases was revealed.

Keywords:

• Nanocomposites
• ferroelectrics
• potassium nitrate
• phase transitions
• restricted geometry
• porous matrix

Funding

A.A. Naberezhnov thanks the Russian Foundation for Basic Research, grant 19-02-00760. In SPbPU, this study was performed as part of the State assignment for basic research (topic code 0784-2020-0025).