Scopus İndeksli Yayınlar Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12416/8651
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Article Phenomenological Study of Lithium-Sodium Tetragermanate Close to the Phase Transition(Springer Nature, 2025) Kiraci, AliThis study presents an analysis of the dielectric and thermal properties in the vicinity of the second-order ferroelectric phase transition, with a specific emphasis on lithium-sodium tetragermanate, LiNaGe<inf>4</inf>O<inf>9</inf>. The power-law equation is employed by modifying the Kouvel-Fisher (KF) technique, which articulates the magnetization () and magnetic susceptibility in relation to the spontaneous polarization () and the dielectric constant () within ferroelectric frameworks. A parallel methodology is adopted to elucidate the heat capacity () and thermal expansivity () in the vicinity of phase transitions occurring in LiNaGe<inf>4</inf>O<inf>9</inf>. We demonstrate that the continuous fluctuations in and with temperature nearing the Curie point (T<inf>C</inf>108 K) as an indication of a second-order transition in LiNaGe<inf>4</inf>O<inf>9</inf>. Furthermore, a linear correlation is also established between and with temperature approaching the Curie point T<inf>C</inf> for this crystal structure. Experimental data are used from the literature for our analysis. Our findings show that the critical behavior of one dielectric or thermal property near the transition temperature in LiNaGe<inf>4</inf>O<inf>9</inf> can be predicted from the other through these linear relationships. The methodology articulated herein for delineating the dielectric and thermal characteristics of LiNaGe<inf>4</inf>O<inf>9</inf> close to the Curie point is extendable to various other ferroelectric materials. © 2025 Elsevier B.V., All rights reserved.Article Citation - WoS: 2Citation - Scopus: 2Phenomenological Study of Manganese Antimonite Close To the Neel Temperature(Ieee-inst Electrical Electronics Engineers inc, 2021) Kiraci, AliThe anomalous behavior of the frequency f and specific heat C-p data for the new layered trigonal (P (3) over bar 1m) form of manganese antimonite (MnSb2O6) was analyzed by means of the power-law relations with the critical exponent alpha in the vicinity of the Neel temperature of T-N= 8.0 K. While the extracted values of a from both f and C-p below T-N (the same value of 0.06) match exactly the value 1/16 (= 0.06) predicted from the three-dimensional (3-D) Ising model, the extracted value of 0.65 from the C-p data above T-N is much higher than the predicted value of 1/8 (= 0.13) from the 3-D Ising model. As an extension of this work, the temperature dependence of the muon-spin relaxation rate (damping constant) lambda of MnSb2O6 was calculated from the pseudospin-phonon-coupled (PS) model and the energy fluctuation (EF) model below T-N. Our results are in good agreement with the data. In addition, the activation energy was calculated from the predicted values of. from both PS and EF models for MnSb2O6. Our results indicate an order-disorder-type transition at T-N = 8.0 K for MnSb2O6.Article A Thermodynamic Study on Pbzr0.52ti0.48o3 Ceramic Close To the Tetragonal-Cubic Transition(Springer, 2020) Kiraci, AliThe isobaric Gruneisen parameter and the wavenumber (frequency) of various Raman modes in PbZr1-xTixO3 (PZT x = 0.48) ceramic were calculated by means of the unit cell volume of this crystal. In addition, the damping constant (linewidth) of the Raman modes studied was computed from the pseudospin-phonon coupled and from the energy fluctuation models close to the tetragonal-cubic transition temperature of T-C = 650 K. This calculation of the damping constant performed in terms of the order parameter (spontaneous polarization), which was associated with the wavenumbers of the Raman modes studied. Furthermore, the inverse relaxation time of the Raman modes in this ceramic calculated and the values of the activation energy were deduced in terms of the Arrhenius plot close to the tetragonal-cubic transition in PZT (x = 0.48) ceramic. Finally, the temperature dependence of some thermodynamic quantities, such as the isothermal compressibility and the specific heat of this ceramic, was predicted.