The two-sublattice model for the incommensurate (INC) phase of NaNO2

Yurtseven H., Sefer Ö.

Philosophical Magazine, 2025 (SCI-Expanded, Scopus) identifier

  • Yayın Türü: Makale / Tam Makale
  • Basım Tarihi: 2025
  • Doi Numarası: 10.1080/14786435.2025.2585242
  • Dergi Adı: Philosophical Magazine
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Chemical Abstracts Core, Compendex, INSPEC
  • Anahtar Kelimeler: incommensurate (INC) phase, Landau theory, NaNO2, Two- sublattice model
  • Marmara Üniversitesi Adresli: Evet

Özet

In this study, we introduce the two-sublattice model applied to the ferroelectric NaNO2. The ferroelectric-incommensurate (FE-INC) and the INC-PE (paraelectric) transitions in NaNO2 are studied within the INC phase of the two sublattice polarisations (P1, P2) by considering their biquadratic coupling, using the Landau mean field theory. Temperature dependences of (P1, P2) and also the inverse susceptibilities (χ1−1, χ2−1) as predicted from the two-sublattice model, are fitted to the experimental data for the INC phase from the literature. It is shown here that the two-sublattice model can explain adequately the observed behaviour of the temperature dependence of the polarisation and susceptibility (dielectric constant) in the INC phase of NaNO2. This is an indication that the two-sublattice model can also be applied to those ferroelectric materials which exhibit the INC phase between the FE and PE phases.