研究目的
Investigating the distribution of electrical polarization and space charge in dielectric materials using focused thermal pulses or waves, with a focus on multi-layer systems and the application of finite element analysis for reconstructing polarization from transient current measurements.
研究成果
Finite element analysis is effective for interpreting thermal-pulse measurements in tightly focused geometries, requiring a multi-physics approach to account for non-uniform heating, anisotropic heat flow, and thermal expansion. Preliminary results show satisfactory agreement between calculated and experimental currents, though further investigation is needed to understand discrepancies in decay rates.
研究不足
The study acknowledges the complexity of analyzing thermal data obtained with a localized heat source due to the ill-posed nature of the inverse problem. The use of pulsed diode lasers with pulse durations in the μs range introduces challenges in modeling the heat source as a Dirac δ-like impulse.
1：Experimental Design and Method Selection:
The study employs finite element analysis (FEA) to model the transient thermal-pulse current for a metal-polymer-metal sample, heated with a Gaussian-shaped laser beam. The methodology involves thermal diffusion, thermal expansion, pyroelectricity, and electrostatics.
2：Sample Selection and Data Sources:
Samples of poly(vinylidene fluoride – trifluoroethylene) (PVDF-TrFE) were prepared with evaporated metal electrodes and poled to a remanent polarization.
3：List of Experimental Equipment and Materials:
A blue diode laser (UltraLasers, 1.5 W cw, λ = 447 nm), Berkeley Nucleonics 565 pulse generator, optical fiber bundle, and computer-controlled X-Y translation stage were used.
4：5 W cw, λ = 447 nm), Berkeley Nucleonics 565 pulse generator, optical fiber bundle, and computer-controlled X-Y translation stage were used.
Experimental Procedures and Operational Workflow:
4. Experimental Procedures and Operational Workflow: The laser beam was focused on the sample, and the transient current was recorded. The sample geometry was defined in Gmsh for FEA simulations.
5：Data Analysis Methods:
The recorded transient current was Fourier-transformed into the frequency domain and converted into a polarization map using the scale transformation method.
独家科研数据包，助您复现前沿成果，加速创新突破
获取完整内容
