We first report the novel Ce3+‐activated and Lu3+‐stabilized gadolinium aluminate garnet (GAG) transparent ceramics derived from their precipitation precursors via a facile co‐precipitation strategy using ammonium hydrogen carbonate (AHC) as the precipitant. The resulting precursors in liquid phase were substantially homogeneous solid solutions and could directly convert into sinterable garnet powders via pyrolysis. Substituting 35 at.% of Lu3+ for Gd3+ was effective to stabilize the cubic GAG garnet structure and transparent (Gd,Lu)3Al5O12:Ce ceramics were successfully fabricated by vacuum sintering at 1715°C. The ceramic transparency was improved by optimizing the particle processing conditions and the best sample had an in‐line transmittance of ~70% at 580 nm (Ce3+ emission center) and over 80% in partial infrared region with a fine average grain size of ~4.5 μm. Transparent (Gd,Lu)3Al5O12:Ce ceramics have a short critical wavelength (<200 nm) and a maximal infrared cut‐off at ~6.6 μm. Both the (Gd,Lu)3Al5O12:Ce phosphor powder and the transparent ceramic exhibited characteristic yellow emission of Ce3+ with strong broad emission bands from 490 to 750 nm upon UV excitation into two groups of broad bands around 340 and 470 nm. The photoluminescence and photoluminescence excitation intensities as well as the quantum yield were greatly enhanced via high‐temperature densification. Both the phosphor powder and ceramic bulk had short effective fluorescence lifetimes.
This paper investigates the excitation and propagation characteristics of a piezoelectric acoustic wave propagating in a rotated Y-cut X-propagating Pb(In0.5Nb0.5)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) relaxor-based ferroelectric single crystal substrate. Numerical simulations were performed to evaluate the acoustic wave properties by FEM software COMSOL. For comparison, two types of structures are taken into consideration: one is the traditional metal electrode/YX-PIN-PMN-PT and the other is silicon dioxide (SiO2) overlay/metal electrode/YX-PIN-PMN-PT substrate. It is shown that shear-horizontal (SH)-type piezoelectric boundary acoustic waves (PBAW) exist in the SiO2 overlay/metal electrode/YX-PIN-PMN-PT substrate and offer a fairly large electromechanical coupling factor K2 of 30%. Compared to a surface acoustic wave excited in the metal electrode/YX-PIN-PMN-PT substrate, enlarged phase velocity and significantly improved quality factor (∼3500) are simultaneously obtained for SH-type PBAW, which are promising for electromechanical transducer applications with high performance.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.