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1.
A new borate single crystal of Sr3Tb(BO3)3 with dimension Ф20×25 mm2 has been grown by the Czochralski method. The grown crystal was characterized by DTA–TGA, FTIR and X-ray powder diffraction analysis. The results showed the crystal with [BO3]3? is congruently melting at 1351.35 °C which belongs to hexagonal structure. The hardness of Sr3Tb(BO3)3 crystal is 422.5 VDH, and is equal to 5.0 moh. The thermal expansion coefficients were determined to be 2.08×10?5/°C along (1 0 0) direction and 7.43×10?6/°C along (0 0 1) direction and the transmission spectrum was measured in 320–1800 nm at room temperature. The magnetic properties of the single crystal were studied which showed its paramagnetism and magnetic anisotropy. The specific Faraday rotation of single crystal was measured at room temperature in 532, 633, and 1064 nm wavelength. The Verdet constants and magneto-optical figures of merit were investigated. The primary emphasis is laid to explore a new magneto-optical material, all the magneto-optical properties of Sr3Tb(BO3)3 are comparing to the ones of TGG. 相似文献
2.
《Journal of Non》2006,352(32-35):3647-3652
The aim of this paper is to present a study of the thermal lens technique in quantifying the thermo optical coefficients: ds/dT (optical path change with temperature), thermal diffusivity and conductivity of PbO–Bi2O3–Ga2O3–BaO glasses doped with Yb3+. The thermal lens results indicate that the heat generation, as a function of the incident wavelength, resembles the absorption band 2F7/2 → 2F5/2 of Yb3+. Thermal diffusivity of 2 × 10−3 cm2/s and thermal conductivity of 4.5 × 10−3 W/K cm were obtained and are similar to other glasses already reported in previous literature. The results emphasize that the thermal lens technique can be a powerful tool to study the heat generation of new glassy systems. 相似文献
3.
Shixing Xia Meng Wang Chunhui Yang Zuotao Lei Guoli Zhu Baoquan Yao 《Journal of Crystal Growth》2011,314(1):306-309
The growth of ZnGeP2 crystals by seeded Vertical Bridgman method was studied. High-quality near-stoichiometric ZnGeP2 single crystals obtained were of 20–30 mm in diameter and 90–120 mm in length. By selection of the seed crystallographic orientation the single crystal ingots without cracks and twins were grown, as shown by X-ray diffraction. The infrared transmission property of the ZnGeP2 crystals was studied by the calculated optical absorption coefficient spectra. The results showed that after thermal annealing of the crystals the optical absorption coefficient was ~0.10 cm?1 at 2.05 μm, and ~0.01 cm?1 at 3–8 μm. The rocking curves patterns of the (4 0 0) reflection demonstrated that the as-grown single crystals possessed a good structural quality. The composition of the crystals was close to the ideal stoichiometry ratio of 1:1:2. The low-loss typical ZnGeP2 samples of 6 mm×6 mm×15 mm in sizes were cut from the annealed ingots for optical parametric oscillation experiments. The output power of 3.2 W was obtained at 3–5 μm when the incident pumping power of 2.05 μm laser was 9.4 W, and the corresponding slope efficiency and the conversion efficiency were 44% and 34%, respectively. 相似文献
4.
We have successfully grown high-purity and -quality PbI2 single crystals by the vertical Bridgman method. The rocking curves of four-crystal X-ray diffraction (XRD) show 120 arcsec in full-width at half-maximum (FWHM). The photoluminescence (PL) spectra at 7.8 K show the resolved intensive exciton emission line and the weak DAP emission band. The deep-level emissions are not observed. The measurement of the electrical and radiographic properties show that Leadiodide (PbI2) single crystal has a resistivity of 5×1010 Ω cm and imager lag is 8 s, respectively. In order to improve the controllability of crystal growth, PbI2 single crystals were also grown from a lead (Pb) excess PbI2 source. The experimental results show very good reproducibility. In addition, the growth models of crystal are proposed, and the growth mechanism is discussed. 相似文献
5.
Yuntao Wu Guohao Ren Dongzhou Ding Fan Yang Shangke Pan 《Journal of Crystal Growth》2012,341(1):46-52
Transparent Lu0.8Sc0.2BO3 crystals doped with 1 at%Ce3+ and co-doped with 1 at% and 3 at%Ga3+ were grown by the Czochralski method. We applied absorption spectrum, luminescence spectra under UV and X-ray excitation, fluorescence decay curve, three dimensional thermoluminescene and X-ray absorption near edge spectroscopy to study the effect of Ga3+ co-doping on the Lu0.8Sc0.2BO3:Ce scintillation crystals. Experimental results indicated that no positive contribution of the Ga3+ ion doping on the scintillation efficiency was found. The causes for the deterioration of scintillation efficiency by co-doping Ga3+ were revealed. The decrease of practical cerium content and the Ce3+/Ce4+ ratio in crystals, and the increase of the trap concentrations, although the corresponding trap types still maintained the same, played a joint influence on the degrading of scintillation efficiency of Lu0.8Sc0.2BO3:Ce crystals. 相似文献
6.
l-Prolinium picrate was synthesized and its solubility in the mixed solvent of acetone and water was estimated. Employing temperature reduction method crystals of size 22×4×3 mm3 were grown. The cell dimensions were obtained by single-crystal X-ray diffraction study. FT-IR, UV–vis–NIR and fluorescence spectral analyses were carried out for the grown crystals. The optical band gap estimated for this crystal is about 2.4 eV. Thermogravimetric study was carried out to determine the thermal properties of the grown crystal. Kurtz powder second harmonic generation (SHG) efficiency measurement revealed that the SHG efficiency is about 52 times that of potassium dihydrogen orthophosphate. Mechanical strength was tested by Vicker's microhardness test. 相似文献
7.
Large single crystals of β-Mn2V2O7 are successfully grown at a slow cooling rate using flux method in a closed crucible. The grown crystals exhibit a characteristic morphology with natural (1 1 0) and (3 5 0) facets. X-ray diffraction and chemical analyses show that the grown crystals have high quality. 相似文献
8.
《Journal of Non》2006,352(23-25):2434-2438
LiGaTe2 crystals have been grown by the Bridgman–Stockbarger technique. The clear transparency range of LiGaTe2 extends from 2.5 to 12 μm and its band-gap at room temperature is at 2.41 eV (515 nm). LiGaTe2 is a positive uniaxial crystal which possesses sufficient birefringence for phase-matching. Its non-linear coefficient d36 estimated by phase-matched second harmonic generation is 43 pm/V ± 10% at 4.5 μm. The properties of LiGaTe2 are compared to those of other mid-IR chalcopyrite non-linear optical crystals with special emphasis on the frequency doubling potential for CO2 lasers operating at 10.6 μm. 相似文献
9.
Kei Kamada Takayuki Yanagida Jan Pejchal Martin Nikl Takanori Endo Kousuke Tsutumi Yoshiyuki Usuki Yutaka Fujimoto Akihiro Fukabori Akira Yoshikawa 《Journal of Crystal Growth》2012,352(1):84-87
Pr:Gd3(Ga,Al)5O12 single crystals were grown by the micro-pulling down (μ-PD) method. All grown crystals were greenish and transparent with 3.0 mm in diameter, 15–30 mm in length. Neither visible inclusions nor cracks were observed. Luminescence and scintillation properties were measured. The substitution at the Al3+ sites by Ga3+ in garnet structure has been studied. In these crystals, Pr3+ 5d–4f emission is observed with 340 nm wavelength. Pr1%:Gd3Ga3Al2O12 shows highest emission intensity. The light yield of Pr:Gd3Ga3Al2O12 sample with 3 mmφ×1 mm size was around 4500 photon/MeV. Scintillation decay time was 7.9 ns (0.5%), 46 ns (0.7%) and 214 ns (98.8%). 相似文献
10.
The europium (Eu2 +) and dysprosium (Dy3 +) codoped melilite (Sr2MgSi2O7) long afterglow phosphors are synthesized with H3BO3 and Li2CO3 fluxes, respectively. The XRD analysis demonstrates similar crystal structure and crystal size of the samples. The SEM presents a better crystallization of samples with flux, other than the one without flux. The excitation and emission spectra of the samples are similar but the decay processes of the afterglow are different. The afterglow properties are enhanced by H3BO3 while they are suppressed by Li2CO3, due to the different concentrations and depths of traps. The sample without flux has a low trap concentration because of the greater surface. Li+ ions reduce the concentration of Sr2 + vacancies and then the trap depth becomes smaller. B3 + ions break the potential balance in oxygen vacancies then the attraction to trapped electron is enhanced. 相似文献
11.
S. Aswartham C. Nacke G. Friemel N. Leps S. Wurmehl N. Wizent C. Hess R. Klingeler G. Behr S. Singh B. Büchner 《Journal of Crystal Growth》2011,314(1):341-348
We have employed the high temperature solutions growth technique and the Bridgman technique to grow cm-size high-quality single crystals of pristine BaFe2As2 (Ba122) and its Co-doped superconducting variants. In the first approach, self-flux (Fe, Co)As was used to achieve a homogeneous melt of composition Ba(Fe, Co)3.1As3.1 at T=1463 K. The melt was then cooled slowly under a temperature gradient in a double-wall crucible assembly to obtain large and flux-free single crystals of Ba(Fe, Co)2As2. In the second approach, single crystals were grown directly from a stoichiometric Ba(Fe, Co)2As2 melt at T=1723 K employing the Bridgman technique associated with a vertical tube furnace. Using both techniques single crystals with lateral dimensions up to 25×10 mm2 and thickness up to 1 mm were obtained. Details of the two methods are given and a comparative study of the magnetic and transport properties of the single crystals obtained using the two methods is presented. 相似文献
12.
Xiaoling He Haitao Zhou Weining Zhou Zhanggui Hu Changlong Zhang Hande Huo Jinliang Wang Yanbin Zuo Fuhua Lu 《Journal of Crystal Growth》2012,351(1):182-187
In this paper the solubility and optical activity of Bi12SiO20 (BSO) single crystals grown in aqueous NaOH under hydrothermal conditions were reported. BSO was found to have a positive solubility coefficient from 350 to 400 °C in 0.5–3 M NaOH, as well as a positive dependence on mineralizer concentration. The reason why additional SiO2 should be introduced in the mineralizer to grow high quality BSO was analyzed. High quality and colorless BSO crystals were grown using 4 M NaOH as a mineralizer and additional 3 wt% SiO2 introduced in the mineralizer. Results showed that the optical activity of hydrothermal colorless BSO was superior to that of BSO grown by the Czochralski (Cz) method. 相似文献
13.
Femtosecond-laser-encoded distributed-feedback color center laser in lithium fluoride single crystal
《Journal of Non》2006,352(23-25):2347-2350
Focused infrared femtosecond laser pulses (wavelength ∼800 nm, emission pulse duration 100 fs) were employed to fabricate optoelectronic devices such as waveguides, micro-gratings and laser active centers in LiF crystals. F2 color centers of about 2 × 1018 cm−3 and refractive index change of about 1% at 633 nm were induced by the fs-laser irradiation. This technique was applied to fabricate a distributed-feedback (DFB) F2 color center laser structure inside LiF single crystal. The LiF DFB laser exhibited laser oscillation at 707 nm at room temperature. The slope efficiency of ∼10% and beam divergence of ∼20 mrad were achieved. 相似文献
14.
《Journal of Non》2005,351(43-45):3468-3475
Luminescence properties and upconversion studies of germanate glasses in ternary GeO2–PbO–Bi2O3 and binary GeO2–Bi2O3 systems containing Er2O3 (0.1–1.0 wt%) are presented for the first time. The Judd-Ofelt parameters found for these glasses are: Ω2 = 4.50 × 10−20 cm2, Ω4 = 1.55 × 10−20 cm2 and Ω6 = 0.69 × 10−20 cm2 for binary glasses and Ω2 = 4.44 × 10−20 cm2, Ω4 = 1.82 × 10−20 cm2 and Ω6 = 0.39 × 10−20 cm2 for ternary glasses. The refractive index of these glasses is found to be ∼2. The transition 4I13/2 → 4I15/2 is peaked at ∼1.53 μm and shows a radiative lifetime around 5 ms. Both systems exhibit similar emission cross-section at 1.53 μm around 0.8 × 10−20 cm2. Upconverted green emission at ∼530 nm (2H11/2 → 4I15/2) and ∼550 nm (4S3/2 → 4I15/2) and red emission at ∼668 nm (4F9/2 → 4I15/2) are observed under 980 nm cw excitation. Our results suggest that these glasses are promising candidates for applications in photonics. 相似文献
15.
Guodong Zhang Xutang Tao Huapeng Ruan Shanpeng Wang Qiong Shi 《Journal of Crystal Growth》2012,340(1):197-201
Using a high purity CdSiP2 polycrystalline charge synthesized in a single-temperature zone furnace, a CdSiP2 single crystal with dimensions of 8 mm in diameter and 40 mm in length was successfully grown by the vertical Bridgman method. The quality of the crystal was characterized by high resolution X-ray diffraction and the full width at half maximum (FWHM) of the rocking curve for the (200) face is 33″. Thermal property measurements show that: the mean specific heat of CdSiP2 between 300 and 773 K is 0.476 J g?1 K?1; the thermal conductivity of the crystal along the a- and c-axes is 13.6 W m?1 K?1 and 13.7 W m?1 K?1 at 295 K, respectively; and the thermal expansion coefficient measured along the a- and c-axes is 8.4×10?6 K?1 and ?2.4×10?6 K?1, respectively. The optical transparency range of the crystal is 578–10,000 nm, and there is no absorption loss in the spectrum from 0.7 to 2.5 μm, as often exists with ZnGeP2 crystals grown from the melt. 相似文献
16.
Glasses in the (Er2O3)x·(B2O3)(60 ? x)·(ZnO)40 system (0 ≤ x ≤ 15 mol%) have been prepared by the melt quenching technique. X-ray diffraction, FTIR spectroscopy, UV-VIS spectroscopy and ab initio calculations studies have been employed to study the role of Er2O3 content on the structure of the investigated glass system.X-ray diffraction and infrared spectra of the glasses reveal that the B–O–B bonds may be broken with the creation of new non-bridging oxygen ions facilitating the formation of Er–O–B linkages. The excess of oxygen can be accommodated in the network by the conversion of sp2 planar [BO3] units to the more stable sp3 [BO4] tetrahedral structural units. The linkages of the [BO4] structural units can polymerize in [B3O9]? 9 cyclic trimeric ions which will produce the ErBO3 crystalline phase. An increase of the efficiency corresponding to the 4I15/2 state to 4I11/2 state (4f–4f) transitions of Er+ 3 ions was observed for the erbium oxide richest glasses.Ab initio calculations on the structure of the matrix network show the thermodynamic instability of the [BO4], [ZnO4] and [Zn4O] structural units. Formation of three-coordination oxygens was necessary to compensate shortage of oxygens from zinc ions. 相似文献
17.
We studied the effect of Dy3+ content on the magnetic properties of cobalt ferrite single crystal. The single crystals of CoFe1.9Dy0.1O4 were grown by the flux method using Na2B4O7.10 H2O (Borax) as a solvent (flux). The black and shiny single crystals were obtained as a product. The X-ray diffraction analysis at room temperature confirmed the spinel cubic structure with lattice constant a=8.42 Å of the single crystals. The compositional analysis endorses the presence of constituents Co, Fe and Dy elements after sintering at 1300 °C within the final structure. The magnetic hysteresis measurements at various temperatures viz. 10 K, 100 K, 200 K and 300 K reveal the soft ferrimagnetic nature of the single crystal than that of for pure CoFe2O4. The observed saturation magnetization (Ms) and coercivity (Hc) are found to be lower than that of pure CoFe2O4 single crystal. The magnetostriction (λ) measurement was carried out along the [001] direction. The magnetic measurements lead to conclude that the present single crystals can be used for magneto-optic recording media. 相似文献
18.
《Journal of Non》2007,353(16-17):1508-1514
This paper reports on the spectroscopic properties and energy transfer in Ga2O3–Bi2O3–PbO–GeO2 glasses doped with Tm3+ and/or Ho3+. From the optical absorption spectra of Tm3+, Judd–Ofelt intensity parameters, radiative transitions probabilities, fluorescence branching ratios, and radiative lifetimes have been calculated using Judd–Ofelt theory. The measured differential scanning calorimetry result shows that the glass exhibits excellent stability against devitrification with ΔT = 129 °C. The measured luminescence spectra show that the 3H4 → 3F4 transition of Tm3+ upon 808 nm laser diode excitation possess a broad full width at half-maximum of ∼126 nm. The maximum value calculated stimulated emission cross-section and the measured lifetime of 3H4 level from the 1.47-μm transition are ∼4.73 × 10−21 cm2 and ∼0.239 ms, respectively. It is noticed that codoping of Ho3+ could significantly enhanced the ratio of the intensity of 1.47–1.80 μm by energy transfer via Tm3+: 3F4 → Ho3+: 5I7. 相似文献
19.
Zn3As2 epitaxial layers were grown on GaAs (1 0 0) substrates by liquid phase epitaxy (LPE) using Ga as the solvent. Zinc mole fraction in the growth melt was varied from 1.07×10?2 to 6×10?2. X-ray diffraction spectrum exhibits a sharp peak at 43.3° characteristic of Zn3As2 crystalline layer. The peak intensity increases with increase in zinc mole fraction in the growth melt. The compositions of the as-grown Zn3As2 layers were confirmed by energy dispersive X-ray (EDX) analysis. Surface morphology was studied using scanning electron microscopy (SEM) and the thickness of the epilayers was also determined. The Hall measurements at 300 K indicate that Zn3As2 epilayers are unintentionally p-doped. With an increase of zinc mole fraction in the growth melt, carrier concentration increases and carrier mobility decreases. Infrared optical absorption spectroscopy showed a sharp absorption edge at 1.0 eV corresponding to the reported band gap of Zn3As2. 相似文献
20.
《Journal of Non》2005,351(49-51):3752-3759
Alkali fluoroborate glass systems containing manganese cations have been thoroughly investigated in order to obtain information about the structural role of manganese in such glass hosts. The amorphous phase of the prepared glass samples R2O–RF–B2O3:MnO (with R = Li and Na) was confirmed from their X-ray diffraction. From the infrared spectra of these glass systems it was concluded that the glass structure contains two group of bands; one due to trigonal BO3 units and the second due to the tetrahedral BO4 units. As manganese was introduced, replacing lithium or sodium, it acts as a network modifier and the intensity of the second group of bands increases at the expense of the first group of bands. The optical absorption spectra of R2O–RF–B2O3:MnO exhibited two conventional absorption bands; one due to Mn2+ ions and the other due to Mn3+ ions. The ESR spectra of these glasses showed a six-line hyper-fine structure centered at g = 2.01 (due to Mn2+ ions) and another signal at g = 4.3 (due to Mn3+ ions). The intensity of optical absorption bands and the ESR signal due to Mn2+ ions decreases with increasing MnO concentration indicating the conversion of Mn2+ ions into Mn3+ ions in the glass network. The thermoluminescence studies on these glass systems showed a quenching of TL output with increase in the concentration of MnO. All the obtained results were discussed on the basis of the glass structure and the conversion of Mn2+ into Mn3+ ions with increasing concentration of MnO in the glass systems. 相似文献