BaCeO3'in rhombohedral-tetragonal faz geçişi için Raman frekansından sıcaklığın bir işlevi olarak hesaplanan sönüm sabiti, dielektrik duyarlılık, ters gevşeme zamanı ve aktivasyon enerjisi

BaCeO3 kristalinin ferroelektrik fazında (Tkatsayısı, dielektrik duyarlılık, ters gevşeme zamanı ve aktivasyon enerji değerleri sıcaklığa bağlı olarak hesaplanmıştır. BaCeO3 kristalinin ortorombik-tetragonal faz geçişinde (TC= 427 K) sönüm katsayısı değerlerini hesaplamak için, sanki spin-fonon çiftlenim ve enerji dalgalanma modellerini kullanarak Raman frekans değerleri düzen parametresi (kendiliğinden polarizasyon) ile ilişkilendirilmiştir. Hesaplanan sönüm katsayı değerlerimiz, gözlemlenen verilerle iyi bir uyum içindedir. Çalışılan Raman kiplerinin ters gevşeme süresi, her iki modelden hesaplanan sönüm sabitinin değerleri ve kendiliğinden polarizasyon (karesi) değerleri kullanılarak öngörülmüştür. Dielektrik duyarlılıkta, Landau fenomenolojik teorisi kullanarak, gözlemlenen Raman frekansları aracılığıyla öngörülmüştür. BaCeO3 kristalinin ferroelektrik fazında, ),>çalışılan Raman kiplerini kullanarak her iki modelden hesaplanan sönüm sabitinden aktivasyon enerjisi değerleride çıkarılmıştır.

Damping constant, dielectric susceptibility, inverse relaxation time and the activation energy calculated as a function of temperature from the Raman frequency for the rhombohedral-tetragonal phase transition in BaCeO3

Temperature dependences of the damping constant (half width at half maximum), dielectric susceptibility, inverse relaxation time and the activation energy using the 110 cm-1 and 125 cm-1 Raman modes are calculated in the ferroelectric phase (Torder parameter (spontaneous polarization) to calculate their damping constants using the pseudospinphonon coupled model and the energy fluctuation model for the orthorhombic-tetragonal transition in BaCeO3 (TC= 427 K). Our calculated values of the damping constant from both models are in good agreement with the observed data. The inverse relaxation time of the studied Raman modes is predicted using the calculated values of the damping constant from both models (PS and EF) and the values of the order parameter (squared). Dielectric susceptibility is also predicted through the observed frequencies of those Raman modes by using the Landau phenomenological theory. The values of the activation energy are also extracted from the damping constant as calculated from both models using the Raman modes studied in the ferroelectric phase of BaCeO3. )>

Keywords:

Damping constant, dielectric susceptibility, inverse relaxation time activation energy, BaCeO3,

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