Nd3+:NaLa(WO4)2晶体的生长和光学性质

Nd3+:NaLa(WO4)2 crystals with a dimension up to 7 mm were grown from a high temperature solution using a double-crucible method. Scanning electron microscopy observations of the crystals showed that there were no small cracks on the surface of the crystals although they underwent two phase transitions when cooling down from high temperatures. X-ray diffraction studies indicated that the as-obtained product is pure low- temperature tetragonal Nd3+:NaLa(WO4)2. The absorption and fluorescence spectra for Nd3+:NaLa(WO4)2 were measured at room temperature. The absorption band at 804 nm has a wide full-width half maximum of 23 nm whose origin is discussed. The absorption and emission cross sections were calculated to be 7.24*10-20 cm2 at 804 nm and 6.54*10-20 cm2 at 1057 nm, respectively.     

Spectral Parameters of Nd^3＋ Ion in Nd^3＋：NaGd（MoO4）2 Crystal

1 INTRODUCTION Since the diode-laser pumped solid-state lasers were found in a wide variety of applications in the fields of military, industry, medical treatment and scientific researches due to the advantages of high stability, compactness, high efficiency and long life- time, the research on more efficient new materials with improved spectral properties for diode pumping has become more important. Molybdate crystals with general formula M’Re(MoO4)2 (M’ = Li, Na, K) have been repor…     

Growth and Spectral Properties of Nd^3＋ Doped KLa（MoO4）2 Crystal

1 INTRODUCTION There has been an increasing interest in the re- search of diode-pumped solid-state lasers in recent years because of the rapid development of high power diode lasers. The absorption peak of Nd3 ions at about 800 nm corresponding to 4I9/2→ 2H9/2 tran- sition is suitable for commercial laser diode GaAlAs pumping[1]. KLa(MoO4)2 is a kind of disordered crystalline host for lasing rare-earth ions[2], and it belongs to Scheelite (CaWO4) structure[3]. The disorder derives…     

P(S)21m相掺钕钼酸钆晶体的结构

标题的晶体是采用提拉法得到的,单晶X射线结构分析表明:化合物分子式(Nd0.023Gd0.977)2(MoO4)3晶体属于四方晶系,空间群为P(S)21m, a=b=7.3556(10) , c=10.685(2)( ), Z=2,Dc=4.563g/cm3,Mr= 1585.64, F(000)=700.00, μ(MoKα)=14.527cm-1,R=0.0463, wR=0.0953,衍射点数为645.Gd(Nd)原子为七配位,Mo原子为四配位.     

^—P421m相掺钕钼酸钆晶体的结构

标题的晶体是采用提拉法得到的,单晶Ｘ射线结构分析表明：化合物分子式（Ｎｄ０．０２３Ｇｄ０．９７７）２（ＭｏＯ４）３晶体属于四方晶系,空间群为＾－Ｐ４２ １ｍ,ａ＝ｂ＝７．３５５６（１０）,ｃ＝１０．６８５（２）＾°Ａ,Ｚ＝２,Ｄｃ＝４．５６３ｇ／ｃｎｍ＾３。Ｍｒ＝１５８５．６４,Ｆ（０００）＝７００．００,μ（ＭｏＫａ）＝１４．５２７ｃｍ＾－１、Ｒ＝０．０４６３,ｗＲ＝０．０９５３,衍射点数为６４     

LiFe(MoO4)2, LiGa(MoO4)2 and Li3Ga(MoO4)3

The structures of lithium iron dimolybdate, LiFe(MoO₄)₂, and lithium gallium dimolybdate, LiGa(MoO₄)₂, are shown to be isomorphous with each other. Their structures consist of segregated layers of LiO₆ bicapped trigonal bipyramids and Fe(Ga)O₆ octahedra separated and linked by layers of isolated MoO₄ tetrahedra. The redetermined structure of trilithium gallium trimolybdate, Li₃Ga(MoO₄)₃, shows substitional disorder on the Li/Ga site and consists of perpendicular chains of LiO₆ trigonal prisms and two types of differently linked Li/GaO₆ octahedra.     

Growth and Spectroscopic Investigations of Disordered Nd3+:Li3Ba2La3(MoO4)8 Crystal

Nd3+: Li3Ba2La3(MoO4)8 crystal has been grown from a flux of Li2MoO4 by the top seeded solution growth method (TSSG) and its structure was confirmed by X-ray diffraction. The polarized absorption spectra, fluorescence spectra and fluorescence decay curve of the crystal were measured. The main spectral parameters were calculated by the Judd-Ofelt theory and compared with other Nd-doped crystals. The broad absorption bands and the large absorption cross sections around 805 nm indicate that the crystal is very suitable for diode-laser pumping. The broad emission bands around 1060 nm show that the crystal is a potential medium for tunable and short pulse lasers. The quantum efficiency of the crystal is up to 95%, which is higher than the value for Nd3+:YVO4 and Nd3+:YAG and comparable to that of other disordered molybdate crystals. The excellent spectroscopic properties show that Nd3+:Li3Ba2La3(MoO4)8 crystal may be regarded as a potential solid state laser host material for diode laser pumping.     

EPR parameters and impurity structures for Cr3+ ions in KSc(MoO4)2, RbIn(MoO4)2 and RbSc(MoO4)2 crystals

The calculations of EPR parameters (g factors g||, g(perpendicular) and zero-field splitting D) related to the impurity structures have been made from the high-order perturbation formulas for Cr(3+) ions in trigonal KSc(MoO(4))(2), RbIn(MoO(4))(2) and RbSc(MoO(4))(2) crystals. It is found that the MO(6) octahedra in these crystals change from the trigonal elongation in the pure crystals to the trigonal compression in the impurity centers. The results are discussed.     

New structure type in the morphotropic series of A 2 + M 2 2+ (MoO4)3: crystal structure of Rb2Cu2(MoO4)3

Isostructural compounds A₂Cu₂(MoO₄)₃ (A = Rb, Cs) were synthesized. The new structure type of the compounds was established for the rubidium-containing compound as an example (a =27.698,b =5.102,c =19.292 å, Β = 707.26?,Z = 8, space group C2/c, R = 0.016). The structure is characterized by pairs of infinite wolframite-like ribbons of CuO₍₄₊₂₎ octahedra stretching along [010] and additionally bridged by MoO₄ tetrahedra. The tetrahedra located between the ribbons weakly interact with each other at distances Mo-O of 2.545 and 2.853 å. There are four such quasione-dimensional copper-molybdenum-oxygen radicals per unit cell; the radicals are united into a single structure by rubidium ions having coordination numbers (CN) 9 and 10.     

Spectral Parameters of Nd^3＋ Ion in Nd^3＋：KLu（WO4）2 Crystal

1 INTRODUCTION There has been increasing interest in the re-search of diode laser-pumped solid-state lasers in re-cent years because of the rapid development of highpower diode lasers. Nd:YAG and Nd:YVO crystalsare commercially available, but limited to low Nd3 (= 1 at.%) doping concentration and to narrow ab-sorption bands near the diode emission wavelengthof 808 nm. Therefore, it is necessary to explore moreefficient crystal materials for diode-pumped solid-state lasers. The alkali …     

Calculation of ligand-field and Stark sub-levels in laser crystals Nd~(3+):KY(WO_4)_2 and Nd~(3+):KGd(WO_4)_2

The parameters of ligand field of laser crystal Na~(3+):KY(WO_4)_2 and Nd~(3+):KGd(WO_4)_2are obtained by a scheme which involved intermediate coupling and ligand field interaction.Thecalculated Stark-levels are in good agreement with the experimental values.     

X-ray and thermal studies of ferroelectric Dy2(MoO4)3

Dysprosium molybdate, Dy₂(MoO₄)₃, displays a ferroelectric phase transition at 145 °C. The X-ray and thermal (DTA, TG and DSC) properties of this compound have been studied. The X-ray study confirmed the ferroelectric phase in the orthorhombic space group Pba2. Thermal analysis demonstrated the existence of a ferroelectric and another phase transition in this compound.

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Zusammenfassung Dysprosiummolybdat, Dy₂(MoO₄)₃ (Abk.: DMO), ein Vertreter der Seltener-denmolybdatreihe zeigt bei 145 °C einen ferroelektrischen Phasenübergang. Röntgendiffraktion und thermische Eigenschaften (DTA, TG, DSC) der genannten Verbindung wurden untersucht. Auf Grund der Röntgendiffraktionsuntersuchung gehört die ferroelektrische Phase in die orthorhombische Raumgruppe Pba2. Mittels Thermoanalyse konnte bei dieser Verbindung die Existenz ferroelektrischer und anderer Phasenübergänge nachgewiesen werden.

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145 °C. (, ) . , Pba2. .

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The authors wish to thank Prof. A. Paul and Mr. R. Bhatnagar for their kind help in some of the experimental work. One of us (MR) gratefully acknowledges a Fellowship from DST, Government of India.     

Phase equilibria in the Tl2MoO4-Nd2(MoO4)3-Hf(MoO4)2 system and the crystal structure of double molybdate TlNd(MoO4)2

The Tl₂MoO₄-Nd₂(MoO₄)₃-Hf(MoO₄)₂ system was studied in the subsolidus region using X-ray powder diffraction. New triple molybdates were found to exist in this system: Tl₅NdHf(MoO₄)₆ (5: 1: 2), TlNdHf_0.5(MoO₄)₃ (1: 1: 1), and Tl₂NdHf₂(MoO₄)_6.5 (2: 1: 4). The first TlNd(MoO₄)₂ single crystals were grown from melt solutions with spontaneous nucleation. Their crystal structure was refined from X-ray diffraction data (Bruker X8 Apex automated diffractometer, MoK _α radiation, 386 F(hkl), R = 0.0136). The tetragonal unit cell parameters are as follows: a = 6.3000(2) Å, c = 9.5188(5) Å, V = 377.80(3) ų, Z = 2, ρ_calcd = 5.876 g/cm³, space group P4/nnc. The structure is a framework built of NdO₈ and TlO₈ tetragonal antiprisms linked via shared lateral edges and alternating in the checkerboard order. Layers share oxygen vertices with MoO₄ interlayer tetrahedra and are linked into the framework.     

Phase equilibria in the Tl2MoO4-Fe2(MoO4)3-Hf(MoO4)2 system and the crystal structure of ternary molybdate Tl(FeHf0.5)(MoO4)3

The subsolidus region of the ternary salt system Tl₂MoO₄-Fe₂(MoO₄)₃-Hf(MoO₄)₂ was studied by X-ray powder diffraction. New compounds Tl₅FeHf(MoO₄)₆ (5: 1: 2) and Tl(Fe,Hf_0.5)(MoO₄)₃ (1: 1: 1). were found to be formed in this system. Crystals of new ternary molybdate of the composition Tl(FeHf_0.5)(MoO₄)₃ were grown by spontaneous flux crystallization. Its composition and crystal structure were refined based on X-ray diffraction data. The mixed three-dimensional framework of the crystal structure is composed of Mo tetrahedra sharing O vertices with (Fe,Hf)O₆ octahedra. The thallium atoms occupy wide channels in the framework.     

Gd3+掺杂对NaY(MoO4)2:Eu3+荧光粉发光性能影响的研究

采用微乳液-水热法制备了NaY(MoO4)2∶Eu3+和Na(Y,Gd)(MoO4)2∶Eu3+荧光粉.利用X射线衍射(XRD)、扫描电镜(SEM)和荧光光谱手段对样品进行了表征.所制样品的X射线衍射峰与标准卡片PDF# 82-2369基本吻合.SEM图谱显示所制备的纳米粒子直径为0.5～0.8μm.激发-发射光谱显示...     

Investigation par analyse thermique differentielle du systeme Gd2(MoO4)3-Bi2(MoO4)3

The phase diagram of the system Gd₂(MoO₄)₃-Bi(MoO₄)₃ has been studied by differential thermal analysis (DTA). Sealed platinum tubes were used as sample holders, in order to prevent the loss of Bi₂O₃ and MoO₃ through volatilization at high temperature. Various solid solutions and new phases are reported: α-Gd_2-x-Bi_x(MoO₄)₃, β -Gd_2-x-Bi_x(MoO₄)₃, α-Bi_2-xGd_x(MoO₄)₃, 3Gd₂(MoO₄)₃·2Bi₂(MoO₄)₃, etc.