The scaling behavior of the dynamic hysteresis of ferroelectric BaTiO3 single crystals was investigated. Two sets of the scaling relation of hysteresis area ⟨A⟩ against frequency f and field amplitude E0 were clearly established. Above the coercive field, the scaling took a form of ⟨A⟩∝f−0.195E00.950. On the other hand, the scaling in the form of ⟨A⟩∝f1.667E0−2.804E04.157 was obtained under subcoercive field condition. While these scaling relations were generally comparable to previously reported ones, it was found that the f and E0 exponents depended on E0 and f, respectively, which was in contrast to the prior theoretical prediction and experimental investigations.

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In this paper, we report the dielectric and ferroelectric response of compositionally graded bilayer and trilayer composites consisting of BaTiO 3 ͑BT͒ and 0.975BaTiO 3 -0.025Ba͑Cu 1/3 Nb 2/3 ͒O 3 ͑BTBCN͒. Two types of graded bilayer samples were synthesized, one with same thickness of BT and BTBCN while other with different layer thicknesses. The graded trilayer sample consisted of BT layer sandwiched between two BTBCN layers of equal thickness. Scanning electron microscopy and transmission electron microscopy images showed a sharp interface with needle-shape domains across the interface. The domain size on BT side was found to be larger than that on BTBCN side. The temperature dependence of dielectric response for all composite systems was found to exhibit shifting in characteristic Curie peak compared to constituent material which was associated to coupling between layers. Moreover, the differences in grain size, tetragonality, domain mobility of each layer was found to perturb the electrical response of composite. The polarization mismatch between uncoupled BT and BTBCN established internal electric field in composite specimen and defined new polarization states in each layer by perturbing free energy functional of the composite specimen. Dynamic hysteresis behaviors and power-law scaling relations of all specimens were determined from polarization-electric field hysteresis loop measurements as a function of frequency. All systems were found to exhibit similar dynamic scaling relationships. Hysteresis area ͗A͘, P r , and E C decreased with increasing frequency due to delayed response but increased with increasing applied electric field due to enhancement of driving force. Trilayer system was found to exhibit strong internal-bias field and double hysteresis behavior. The coupling effect resulting due to polarization mismatch between layers had substantial influence on the dynamic hysteresis behavior and power-law scaling relations.

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Crystal-structure dependent dynamic scaling behavior was investigated for BaTiO3 ceramic. The scaling relation of the form , (where is the area under the hysteresis loop, while f and E 0 represent the frequency and amplitude of the applied electric field signal) was used to determine the values of parameters m and n at various temperatures in the range of −90 °C to 170 °C. The variations in the values of parameters m and n with temperature are explained in terms of the effect of the crystallographic nature of BaTiO3. The values of parameters m and n obtained for the paraelectric regime suggest that the hysteresis in the P–E (polarization–electric field) loops is related to the dielectric loss rather than any domain-related phenomenon.