Anharmonicity ofBaTiO3single crystals

Abstract

By analyzing the dielectric non-linearity with the Landau thermodynamic expansion, we find a simple and direct way to assess the importance of the eighth order term. Following this approach, it is demonstrated that the eighth order term is essential for the adequate description of the para/ferroelectric phase transition of BaTiO 3 . The temperature dependence of the quartic coefficient β is accordingly reconsidered and is strongly evidenced by the change of its sign above 165 o C. All these findings attest to the anomalously strong polarization anharmonicity of this material, which is unexpected for classical displacive ferroelectrics.

Non-Linear Dielectric Response of Ferroelectrics, Relaxors and Dipolar Glasses

“…The bias field amplitude may reach values up to 5.5·10 7 Vm -1 (Leont'ev et al, 2003). In barium titanate a strong dc field induces the PT between paraelectric and ferroelectric phases (Wang et al, 2006). By changing the value of the dc electric field the local slope of the polarization curve is probed in many points.…”

Effects of the surface charge screening and temperature on the vortex domain patterns of ferroelectric nanodots

“…Under the condition of applied stress, the LandauDevonshire energy density f LD should be a function of the spontaneous polarization and stress. In this work, an eighthorder polynomial of the modified Landau-Devonshire energy density is adopted as [41][42][43] …”

Флуктуации, Высшие Ангармонизмы И Разложение Гинзбурга - Ландау - Девоншира Для Титаната Бария

“…Одна из мотиваций учета членов типа P 8 первоначально состояла в том, чтобы устранить сильную темпера-турную зависимость коэффициентов B 1 и B 2 [10]. Позже, однако, было установлено, что таким способом данную проблему решить не удается [11], [12].…”