Phenomenological approaches on the Nd3+ doped ferroelectric LaBGeO5

Kara N., Kiraci A., YURTSEVEN H. H.

FERROELECTRICS, cilt.572, sa.1, ss.13-26, 2021 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 572 Sayı: 1
  • Basım Tarihi: 2021
  • Doi Numarası: 10.1080/00150193.2020.1868869
  • Dergi Adı: FERROELECTRICS
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Chemical Abstracts Core, Compendex, INSPEC
  • Sayfa Sayıları: ss.13-26
  • Orta Doğu Teknik Üniversitesi Adresli: Evet

Özet

Two phenomenological models, namely the compressible Ising model and Landau model, have been used to analyze the specific heat and the dielectric constant data, respectively for the pure and Nd3+ doped LaBGeO5 (LBG) crystals. The critical exponent of the specific heat was extracted in both ferroelectric and paraelectric phases of the crystals studied here within the temperature intervals of [T - T-C vertical bar < 4 K. The extracted values of the critical exponent were then used to predict some thermodynamic quantities such as the enthalpy, entropy, and the Gibbs free energy. Regarding the analysis of dielectric constant data within the framework of the Landau theory, the observed values of the birefringence were associated with the order parameter below the transition temperature T-c. The Landau coefficients a(0) and a(4) were determined. Our results indicate a second-order phase transition mechanism.