•CaWO4 crystal with large size was grown successfully by Bridgman method.•The optical properties of CaWO4 crystal were investigated in detail.•Mechanism of slow luminescence decay of CaWO4 crystal was proposed.•Significant data of scintillation properties of CaWO4 crystal were presented.CaWO4 single crystal with large size was grown by Bridgman method. The results of transmission spectra show that the transmittance of CaWO4 crystal reaches 79–85% in 320–800 nm wavelength range. The refraction index is near 1.80 in visible and infrared region. CaWO4 crystal shows a broad emission band centered at 424 nm under X-ray excitation and centered at 416 nm under ultraviolet (λex = 280 nm) excitation. The decay kinetics of CaWO4 single crystal shows double-exponential decay with fast decay constant τ1 = 5.4 μs and slow decay constant τ2 = 177.1 μs. The energy resolution of CaWO4 crystal was found to be 31.6% in the net peak of 545.9 channel. Meanwhile, the absolute output is at the lever of 19,000 ± 1000 photons/MeV. The results indicate the scintillator of CaWO4 single crystal has great potential in the applications of high-energy physics and nuclear physics due to its high light output and great energy resolution.

•New (Lu1 − xInx)2O3 (x = 0–1) solid solution materials have been prepared by a facile co-precipitation technique.•The underlying mechanisms of In3 + substitution for Lu3 + are deciphered.•The resultant solid solutions allow to fully dissolve the rare-earth activator for various optical applications.A series of (Lu1 − xInx)2O3 (x = 0–1) powders have been synthesized by a facile co-precipitation route using ammonium hydrogen carbonate (AHC) as the precipitant. The effects of In3 + substitution for Lu3 + on the particle properties, structure features and optical performances of the materials were systematically investigated. The results show that (1) the (Lu1 − xInx)2O3 precursor samples with x = 0–0.5 possess a chemical composition of basic carbonate, however, the precursor specimen with x = 1 is hydrated oxyhydroxide; (2) In3 + addition significantly affects the nucleation kinetics of the binary Lu–In system, leading to the empty interiors inside the precursors; (3) calcining the resultant precursors directly yields well-dispersed (Lu1 − xInx)2O3 oxide particles with ultrafine sizes of ~ 65 nm; (4) both the lattice parameters and theoretical densities of the solid solutions linearly decrease along with increasing In3 + incorporation; (5) In3 + doping apparently red-shifts the absorption edge of UV–vis absorption spectroscopy and the bandgap energies of the (Lu1 − xInx)2O3 oxide powders generally decrease at a higher In3 + content.Download high-res image (86KB)Download full-size image

According to the molar ratio of 0.25Pb(In1/2Nb1/2)O3–0.44Pb(Mg1/3Nb2/3)O3–0.31PbTiO3, PIMNT polycrystalline material was prepared by using the two-step columbite precursor route. Using the polycrystalline material prepared by solid-state reaction, 55 mm in diameter PIMNT single crystals with [1 1 0] orientation had been grown successfully by the seeded vertical Bridgman process with the optimum conditions. The crystal wafers on the [0 0 1]-cut were fabricated from the crystal boules oriented by the rotating orientation XRD method. As-grown crystal exhibits a peculiar phase evolution from rhombohedral to tetragonal phase along the growth direction due to the composition segregation in the crystal growth. As for [0 0 1]-oriented wafers fabricated from rhombohedral phase region, the crystal wafers exhibit a piezoelectric coefficient d33 of 1500–2100 pC/N, a dielectric permittivity ɛ of 4600–5800 and a dielectric loss tan δ of 0.5–1%. Compare to the binary crystal PMNT, the ternary crystal wafers possess a higher phase transition temperature Tr−t of 100–120 °C, a higher Curie temperature Tc of 160–195 °C and a larger coercive field Ec of 4.2–5.0 kV/cm, which are favorable for the higher power ultrasonic devices with a wider working temperature range.Graphical abstractHighlights► PIMNT single crystal as large as Ø55 × 100 mm was grown successfully by seeded vertical Bridgman process described in this work. ► The intrinsic phase evolution of PIMNT crystal boule together with the distribution of piezoelectric coefficient were revealed. ► As-grown crystal boule with a high percentage of rhombohedral region enables a significant improved usage ratio as a piezoelectric material with high performances. ► PIMNT crystal wafers with excellent electrical properties have been practically applied in the manufacture of sonar transducers and ultrasonic motors.

Growth of LaCl3:Ce3+ crystal by the vertical Bridgman process in non-vacuum atmosphere has been studied. Based on the dehydration procedure of LaCl3·7H2O and CeCl3·7H2O investigated by DTA/TG, anhydrous LaCl3 and CeCl3 were prepared by heating LaCl3·7H2O and CeCl3·7H2O at 200–230 °C for 6–7 h in dried HCl atmosphere. Using the feed materials prepared from the anhydrous lanthanon chlorides, a 4 mol% Ce3+ doped LaCl3 crystal with a size of Ø 28 mm × 70 mm was successfully grown. The crystal was grown under the optimum conditions such as a growth rate of 0.5–0.8 mm/h and a temperature gradient of around 30 °C/cm across solid–liquid interface at a furnace temperature of 940–960 °C. The Bridgman process is confirmed to be promising for growing large size LaCl3:Ce3+ crystals with high quality.

The growth of bismuth tellurite crystals by the vertical Bridgman method has been reported in this paper. The volatilization of melt is avoided by sealing the double-shell platinum crucibles and the cracking of crystals is decreased under smaller temperature gradients in the Bridgman furnace. By means of the optimum conditions such as stoichiometric feed materials, growth rate of 0.5∼0.8 mm/h and the temperature gradient of 30∼35 °C/cm across the solid–liquid interface under the furnace temperature of 980∼1000 °C, the single crystals have been grown successfully by the vertical Bridgman method. This work proves that the vertical Bridgman process is promising to grow the high quality crystals with improved physical properties.