In this paper, the effective pyroelectric coefficient and polarization offset of the compositionally step-like graded multilayer ferroelectric structures have been studied by use of the first-principles approach. It i...In this paper, the effective pyroelectric coefficient and polarization offset of the compositionally step-like graded multilayer ferroelectric structures have been studied by use of the first-principles approach. It is exhibited that the dielectric gradient has a nontrivial influence on the effective pyroelectric coefficient, but has a little influence on the polarization offset; and the polarization gradient plays an important role in the abnormal hysteresis loop phenomenon of the co.mpositionally step-like graded ferroelectric structures. Moreover, the origin of the polarization offset is explored,which can be attributed to the polarization gradient in the compositionally step-like graded structure.展开更多
The characterization of pyroelectric materials is essential for the design of pyroelectric-based devices.Pyroelectric current measurement is the commonly employed method,but can be complex and requires surface electro...The characterization of pyroelectric materials is essential for the design of pyroelectric-based devices.Pyroelectric current measurement is the commonly employed method,but can be complex and requires surface electrodes.Here,we present noncontact electrostatic voltmeter measurements as a simple but highly accurate alternative,by assessing thermally-induced pyroelectric surface potential variations.We introduce a refined model that relates the surface potential variations to both the pyroelectric coefficient and the characteristic figure of merit(FOM)and test the model with square-shaped samples made from PVDF,LiNbO3 and LiTaO3.The characteristic pyroelectric coefficient for PVDF,LiNbO3 and LiTaO3 was found to be 33.4,59.9 and 208.4μC m−2 K−1,respectively.These values are in perfect agreement with literature values,and they differ by less than 2.5%from values that we have obtained with standard pyroelectric current measurements for comparison.展开更多
文摘In this paper, the effective pyroelectric coefficient and polarization offset of the compositionally step-like graded multilayer ferroelectric structures have been studied by use of the first-principles approach. It is exhibited that the dielectric gradient has a nontrivial influence on the effective pyroelectric coefficient, but has a little influence on the polarization offset; and the polarization gradient plays an important role in the abnormal hysteresis loop phenomenon of the co.mpositionally step-like graded ferroelectric structures. Moreover, the origin of the polarization offset is explored,which can be attributed to the polarization gradient in the compositionally step-like graded structure.
基金supported by the European Horizon 2020 grant“SensApp”under Grant Agreement No.829104.
文摘The characterization of pyroelectric materials is essential for the design of pyroelectric-based devices.Pyroelectric current measurement is the commonly employed method,but can be complex and requires surface electrodes.Here,we present noncontact electrostatic voltmeter measurements as a simple but highly accurate alternative,by assessing thermally-induced pyroelectric surface potential variations.We introduce a refined model that relates the surface potential variations to both the pyroelectric coefficient and the characteristic figure of merit(FOM)and test the model with square-shaped samples made from PVDF,LiNbO3 and LiTaO3.The characteristic pyroelectric coefficient for PVDF,LiNbO3 and LiTaO3 was found to be 33.4,59.9 and 208.4μC m−2 K−1,respectively.These values are in perfect agreement with literature values,and they differ by less than 2.5%from values that we have obtained with standard pyroelectric current measurements for comparison.
