摘要 :
A quantitative measurement method of the linear and nonlinear dielectric constant using cantilever-type scanning nonlinear dielectric microscopy (SNDM) is reported. Using this method, we succeed in quantitatively measuring the lin...
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A quantitative measurement method of the linear and nonlinear dielectric constant using cantilever-type scanning nonlinear dielectric microscopy (SNDM) is reported. Using this method, we succeed in quantitatively measuring the linear dielectric constant distribution of TiO_2-Bi_2Ti_4O_(11) ceramics and nonlinear dielectric constant of LiTaO_3 single crystal.
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The field-induced polarization state and the phase transition to a relaxor in Pb(Zn_(1/3)Nb_(2/3))O_3 (PZN) were investigated. It was confirmed that the field-induced polarization state in PZN can be realized by applying an electr...
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The field-induced polarization state and the phase transition to a relaxor in Pb(Zn_(1/3)Nb_(2/3))O_3 (PZN) were investigated. It was confirmed that the field-induced polarization state in PZN can be realized by applying an electric field at room temperature for a long time. The phase transition from the field-induced polarization state to a relaxor was observed at 114℃ during zero-field heating (ZFH) after applying an electric field even at room temperature. The critical slowing down of this transition was observed, where the dielectric dispersion was almost of the single Debye type with β = 0.95. The second- and third-order nonlinear dielectric constants were measured during ZFH. The sharp peak at 114℃ with a negative value in the third-order nonlinear dielectric constant was found. The field-induced polarization state and phase transition in PZN were discussed.
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Recently, we have proposed and developed the SNDM, which is a new, purely electrical technique for imaging the state of ferroelectric polarization and the local crystal anisotropy of dielectric materials. This time, we investigate...
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Recently, we have proposed and developed the SNDM, which is a new, purely electrical technique for imaging the state of ferroelectric polarization and the local crystal anisotropy of dielectric materials. This time, we investigated the new functions of SNDM, which are measurement of the higher order nonlinear dielectric constant and the vertical resolution of SNDM. It is expected to obtain the higher resolution by the higher order measurement than that by the conventional SNDM imaging. Moreover, using the very high vertical resolution of SNDM, a new microscopy for measuring the microscopic topography and a new displacement sensor for the very small will be available.
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An improvement of the description of the nonlinear behavior of PZT piezoelectric ceramics is proposed. The current obtained when applying a low frequency and high voltage harmonic signal is analyzed using a bridge, built ad hoc. T...
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An improvement of the description of the nonlinear behavior of PZT piezoelectric ceramics is proposed. The current obtained when applying a low frequency and high voltage harmonic signal is analyzed using a bridge, built ad hoc. The validity of no model is presupposed in the processing of data. Nonlinear behavior depends explicitly on the amplitude of the applied field. The nonlinear increment of the dielectric constant can be split into three fractions: the first one epsilon_(alpha), is directly related to the losses, does not depend on the instantaneous field, and is larger in non aged ceramics. None of these effects occurs with the second fraction epsilon_(beta), related to reversible processes. The dependence of those terms on the field amplitude is of the power type, with fractional power that depends on the ceramic type.
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Dependence of the dielectric nonlinearity a_3 on temperature has been determined in PMN single crystal. A crossover from the decreasing paraelectric-like to the increasing glass-like temperature behavior has been observed in the s...
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Dependence of the dielectric nonlinearity a_3 on temperature has been determined in PMN single crystal. A crossover from the decreasing paraelectric-like to the increasing glass-like temperature behavior has been observed in the static a_3 on cooling towards the freezing transition in the absence of electric field. It is shown that this crossover is actually predicted by the spherical random bond-random field model of relaxor ferroelectrics. Results support the idea that relaxor systems, at zero electric field undergo a transition into a low-temperature glassy state.
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The first, #epsilon#_1 and third harmonic dielectric response #epsilon#_3 have been simultaneously measured in disordered perovskite relaxors PMN single crystal and 9/65/35 PLZT ceramics, uniaxial relaxor ferroelectric SBN:Ce sing...
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The first, #epsilon#_1 and third harmonic dielectric response #epsilon#_3 have been simultaneously measured in disordered perovskite relaxors PMN single crystal and 9/65/35 PLZT ceramics, uniaxial relaxor ferroelectric SBN:Ce single crystal, and ferroelectric single crystal TGS. The temperature dependences of the static dielectric constant and dielectric nonlinearity #alpha#_3 =#epsilon#_3/#epsilon#_1~4 show that in zero electric field disordered perovskite relaxors undergo a freezing transition into nonergodic glassy phase, while in uniaxial relaxors spontaneous breaking of relaxor freezing into the ferroelectric state occurs.
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In the present paper, we describe theoretically the disappearance of self-focusing nonlinear response in the layers near the crystal surface with totally shielding cover due to the electric field variation. The regularities of the...
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In the present paper, we describe theoretically the disappearance of self-focusing nonlinear response in the layers near the crystal surface with totally shielding cover due to the electric field variation. The regularities of the formation of a linear near-surface layer due to an increase in the field strength are described. The five types of surface waves from nonlinear wave equation satisfying five different sets of boundary conditions are found. The power flows carried by surface waves are calculated for each type of waves in order to analyze the energy redistribution that occurs in the near-surface layers due to the wave propagation. It is found that the redistribution of the surface wave energy between the crystal regions is possible by varying the surface amplitude, surface gradient or gradient of the field at the domain boundary.
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We have measured the linear and the third-orderdielectric constants of an antiferroelectric liquid crystalMHPOBC and mixtures of R and S-enantiomers. In the opticallypure and nearly pure samples with the SmC_(#alpha#)*, whilethe l...
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We have measured the linear and the third-orderdielectric constants of an antiferroelectric liquid crystalMHPOBC and mixtures of R and S-enantiomers. In the opticallypure and nearly pure samples with the SmC_(#alpha#)*, whilethe linear dielectric constant is continuous with a small change ofthe slope in its temperature dependence. These behaviors werewell explained by the Landau theory. The optical puritydependence of the Curie constant was also investigated. TheCurie constant slightly decreases as the optical purity is reduced,as predicted by the Landau theory.
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Nonlinear contributions to the dielectric response have been investigated by the quasistatic charge accumulation technique and by monitoring the first and the third harmonic dynamic response in PMN single crystal and PLZT ceramics...
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Nonlinear contributions to the dielectric response have been investigated by the quasistatic charge accumulation technique and by monitoring the first and the third harmonic dynamic response in PMN single crystal and PLZT ceramics. Additional contribution to the nonlinearity of the quasistatic and first harmonic responses is identified. This contribution can be considered within the spherical random bond random field model by expanding the mean ferroelectric coupling constant J_0(E) as a function of the field.
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The quasistatic linear and nonlinear dielectric constants #epsilon#_s in lead magnesium niobate (PMN (111) AND PMN (001)) crystals were investigated by means of the charge accumulation technique. The zero-field-cooled and field-co...
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The quasistatic linear and nonlinear dielectric constants #epsilon#_s in lead magnesium niobate (PMN (111) AND PMN (001)) crystals were investigated by means of the charge accumulation technique. The zero-field-cooled and field-cooled static susceptibilities show a crossover from a nonergodic relaxor to inhomogeneous ferroelectric behavior. At electric fields above the critical value contribution from the saturated spontaneous polarization was observed. The temperature dependence of the total third order nonlinear response was also determined along both axis.
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