Papers by Keyword: P-E Hysteresis Loop

Abstract: In this paper, the PZT nano-ceramics were prepared by an improved Sol-Gel method. This method was based on recording to A.S.Mischenko. TF Analyzer 2000 FE was used to measure the ferroelectric properties of the samples. The results show the change trends of the P-E hysteresis loops in different voltages, temperatures and frequencies. Impedance was tested by precision impedance analyzers 6500 series. With the use of the equivalent circuit to simulate the piezoelectric ceramic vibrator we can get a conclusion that in the 85 MHz-120 MHz the response of the sample can be represented with a RLC series resonant circuit. The resonant frequency of the sample is 97.12MHz, and the loss is very low. Compared with the general piezoelectric vibrator PZT 95/05 nano-ceramic is a low frequency capacitor with the capacitance tend to 0 F.

Abstract: The growth of strontium doped barium titanate (BST) powder is performed by solid-state reaction. Microstructural characterization by SEM technique confirms the BST film is successfully formed on p-Si (100) substrate by spin coating technique. Dielectric properties of MFIS (Metal/ Ferroelectric/ Insulator/ Semiconductor) designs are measured by impedance analyzer (LCR meter, QuadTech :1730). P-E (polarization-electric field) hysteresis loops are also measured by applying the same triangular wave electric field in order to allow their application in NVFeRAM (Non-Volatile Ferroelectric Random Access Memory). The maximum remanent polarization density (P_r=38.6µC/cm²) is found at BST film 600°C. The film exhibits the potential to be a future promising memory. The results obtained from this research are quite interesting, acceptable, credible and applicable in use for NVFeRAM.

Abstract: Mn-doped Na0.5K0.5NbO3 (NKN) crystals have been grown by self-flux method under several heat-treatment conditions. The cooling rate affected the quality of Mn-doped NKN crystals significantly. When the cooling rate was 0.5 oC/min at temperatures ranging from 1050 to 950 oC, the synthesized Mn-doped NKN crystal exhibited a single nucleation growth, compared with multinucleation growth when the cooling rate was 0.25 oC/min at temperatures ranging from 1050 to 950 oC. The frequency dependence on the ferroelectric P-E hysteresis loop of the Mn-doped NKN crystal was not observed at measurement frequency of 0.1 – 25 Hz. The annealed 0.5 mol% Mn-doped NKN crystal exhibited excellent P-E hysteresis loop with Pr of 45.0 μC/cm2 and Ec of 7.2 kV/cm.

Abstract: Giant electromechanical coupling factor of k31 mode over 86% was found for (100) Pb[(Zn1/3Nb2/3)0.91Ti0.09]O3 and (110) Pb[(Mg1/3Nb2/3)0.74Ti0.26]O3 single-crystal plates poled in the [100] and [110] directions, respectively. The P-E hysteresis loops in the single-crystal plates with giant k31 became asymmetric. Furthermore, the frequency response of impedance in these plates with giant k31 consisted of a single vibration in the length direction. A mechanism to realize giant k31 can be explained by the relationship between the crystal plane and poling direction. In addition, the existence of giant piezoelectric d31 constant was proven by the strain measurement as well as by the impedance measurement.