High sensitivity gravimetric sensor made of unidirectional carbon fiber epoxy composite on （1 -- x）Pb（Znl/3Nb2/3）O3-xPbTiO3 single crystal substrate

We have derived a general formula for sensitivity optimization of gravimetric sensors and have used it to design a high sensitivity gravimetric sensor using unidirectional carbon fiber epoxy composite （CFEC） waveguide layer on （1 -x）Pb（Znl/3Nbz/3）O3-xPbTiO3 （PZN-xPT） single crystal substrate with the carbon fibers parallel to the xj and x2 axes, respectively. The normalized maximum sensitivity （｜sfm｜λ）max exhibits an increasing tendency with the decrease of （h/λ）opt and the maximum sensitivity （｜sfm｜λ）max increases with the elastic constant c6E6 of the piezoelectric substrate material. For the CFEC/[011]c poled PZN-7%PT single crystal sensor configuration, with the carbon fibers parallel to the xa axis at λ = 24 ktm, the maximum sensitivity ｜sfm｜max can reach as high as 1156 cmZ/g, which is about three times that of a traditional SiO2/ST quartz structure gravimetric sensor. The better design selection is to have the carbon fibers parallel to the direction of propagation of Love wave in order to obtain the best sensitivity.     

High pyroelectric power generation of 0.7Pb(Mg1/3Nb2/3)O3–0.3PbTiO3 single crystal

We report the pyroelectric power generation of a relaxor ferroelectric 0.7Pb(Mg_1/3Nb_2/3)O₃–0.3PbTiO₃ (PMN–PT) single crystal. For a temperature variation rate of 0.5 K/s, the PMN–PT generated a closed-circuit current of 10 nA and an open-circuit voltage of 1.1 V at room temperature. The pyroelectric current and voltage of the PMN–PT single crystal were proportional to the temperature variation rate and were sharply enhanced near the structural phase-transition temperature. Additionally, the PMN–PT pyroelectric generator produced stable power for excessive thermal cycling and was highly sensitive to random thermal fluctuations. Our results indicate the potential importance of PMN–PT for high-power pyroelectric generator applications.     

Magnetoelectric effect in laminates of polymer-based pseudo-1–3 (Tb0.3Dy0.7)0.5Pr0.5Fe1.55 composite and?0.3Pb(Mg1/3Nb2/3)O3–0.7PbTiO3 single crystal

We report an extrinsic magnetoelectric effect in composite laminates made by sandwiching one thickness-polarized 0.7Pb(Mg_1/3Nb_2/3)O₃–0.3PbTiO₃ (PMN–PT) piezoelectric single crystal plate between two length-magnetized, polymer-based pseudo-1–3 (Tb_0.3Dy_0.7)_0.5Pr_0.5Fe_1.55 magnetostrictive composite plates. The laminates exhibit large magnetoelectric voltage coefficients (α _V ) of ∼0.17 V/Oe with a flat response for frequencies in excess of 40 kHz and of ∼2.97 V/Oe at the natural resonance frequency of ∼65 kHz. The distinct advantages of the laminates include high magnetic field sensitivity, low Joule heating loss, wide operating bandwidth, and low cost.     

The transverse laser induced thermoelectric voltages in step flow growth （1-x）Pb(Mg1/3Nb2/3)O3-xPbTiO3 thin films

This paper reports that the transverse laser induced thermoelectric voltages (LITV) are observed for the first time in the step flow growth (1-x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT,x = 0.20, 0.33, 0.50) thin films deposited on vicinal-cut strontium titanate single crystal substrates. Because lead magnesium niobate-lead titanate is a solid solution of lead magnesium niobate (PMN) and lead titanate (PT), there are two types of signals. One is wide with a time response of a microsecond, and the other superimposed with the wide signal is narrow with a time response of a nanosecond. The transverse LITV signals depend on the ratio of PMN to PT drastically. Under the irradiation of 28-ns pulsed KrF excimer laser with the 248-nm wavelength,the largest induced voltage is observed in the 0.50Pb(Mg1/Nb2/3)O3-0.50PbTiO3 films. Moreover, the effects of film thickness, substrates, and tilt angles of substrates are also investigated.