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Journal of Rare Earths 2019年第11期37卷 1255-1260页

作者： Lukasz marek marcin Sobczyk Victor A.Trush Kamil Korzeniowski Vladimir m.Amirkhanov Janina Legendziewicz Faculty of Chemistry University of WroctawuL E Joliot-Curie 1450-383 WrociawPoland Department of Chemistry Kyiv National Taras Shevchenko UniversityVolodymyrska Street 64Kyiv 01601Ukraine

In recent years there has been growing interest in lanthanide-based multifunctional materials that exhibit interesting photophysical *** work presents spectroscopic and crystallographic characterization of a new dysprosium complex with sulfonylamidophosphate *** crystal structure of[Nady(SP)4]2·i-PrOH was determined and *** turns out that the dy(Ⅲ)complex is not isostructural with earlier reported compounds and crystallizes in the monoclinic system(space group P21).Two crystallographically independent dysprosium atoms are in eight-fold coordination,with a triangular dodecahedron ***,emission(77 and 300 K)and excitation spectra as well as fluorescence decay time measurements allowed optical characterization of obtained *** energy transfer from SP-ligand to dy^3+ion has been *** Judd-Ofelt theory was applied to predict fundamental fluorescence properties of dy^3+ion in the title *** Judd-Ofelt intensity parameters were used to determine the emission transition probabilities,fluorescence branching ratios and radiative lifetime of the emitting 4F9/2 *** obtained results indicate that the investigated chelate can be a potential candidate for OLEDs emitting yellow light.

关键词： dy^3+ Sulfonylamidophosphates Crystal structure Absorption and emission spectra Judd-Ofelt intensity calculations Energy transfer

Phase Formation and magnetic Properties of Nanocomposite Nd-Fe-B Adjusted by Small Amount of dy and Co

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Journal of Rare Earths 2004年第z2期22卷 89-94页

作者： T S Jang T W Lim H S Aum D H Lee m B Kim Division of materials and Chemical Engineering Sun Moon UniversityKorea Division of Materials and Chemical EngineeringSun Moon UniversityKorea Division of Mechanical EngineeringSun Moon University 100 Kalsan LiTangjung MyonAsan CityChoongnam 336-708Korea Division of Materials and Chemical EngineeringSun Moon UniversityKorea Division of Materials and Chemical EngineeringSun Moon UniversityKorea

In order to improve and stabilize the magnetic properties of nanocomposite Nd2Fe14B/α-Fe magnetic alloys by a compositional adjustment, small amount of dy and/or Co was added to Nd9Fe84B7 alloys. DTA analysis on the amorphous of the alloys took place as the soft magnetic phases were crystallized, and then the hard magnetic Nd2Fe14B was precipitated from them. While α-Fe and a metastable 1:7 (TbCu7-type) phase were formed simultaneously in dy and Co-free alloys, they were crystallized separately at different temperatures after dy or Co was added. This phase separation occurred more clearly in the dy-treated alloys and the other soft magnetic phase Fe3B was also stabilized by dy and/or Co. The 1: 7 phase that was stabilized by dy and/or Co was not eliminated at 700 ℃, decreasing magnetic properties of the alloys. It was eventually disappeared above 725 ℃, but Fe3B was not eliminated even at 750 ℃ when dy was added more than 0.5 at% or Co was added more than 2.0 at%. Amount of Nd2Fe14B in the alloys tended to increase as dy addition increased,whereas Co addition did not lead to any appreciable change in the ratio of α-Fe and Nd2Fe14B. moreover, dy addition apparently increased coercivity of an alloy while Co addition had a beneficial effect on remanence. The grains in the dytreated alloys were usually finer than those in the Co-treated alloys. The grain size of both α-Fe and Nd2Fe14B in the alloys exhibiting mr ≥ 0.72 was in the range of 20 ～ 40 nm or even larger 50 nm, which is larger than the theoretical optimum size ( ～ 10 nm). Typical magnetic properties obtained from a Nd7.5dy1.5Fe82.5Co1.5B7 alloy annealed for 12 min at 725 ℃were iHc=4.85 kOe, Br= 11.32 kG, (BH)max = 15.73 mGOe, and mr=0.73.

关键词： nanocomposite Nd-Fe-B magnetic properties remanence coercivity

Spectral analysis in ultraweak emissions of chemi-and electrochemiluminescence systems

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Journal of Rare Earths 2009年第4期27卷 593-597页

作者： K.Staninski m.Kaczmarek S.Lis D.Komar A.Szyczewski Faculty of Chemistry Adam Mickiewicz University Faculty of Physics Adam Mickiewicz University

Investigation of ultraweak emissions in the processes of chemiluminescence, CL, and electrochemiluminesce, ECL, requires special techniques of their recording and spectral analysis. From among the hitherto proposed methods of detection of the emission spectra of these processes, that of the cut-off filter was most sensitive. The usefulness of this method in interpretation of the CL and ECL systems of the quantum yields in the range 1×10^-9-1×10^-11 containing ions and complexes of Eu（Ⅲ）, Tb（Ⅲ） and dy0ID was shown. Exceptional character of the emission bands of lanthanide ions, being a result of the f-f electron transitions and in particular their low FWHm, permitted the appli- cation of the cut-off filter method to their analysis. The results obtained for CL and ECL on the basis of analysis of ultraweak emission proved to be successful in analytical applications. The systems containing Eu（Ⅲ） ions hydrated or complexed with organic ligands enabled inferring changes in the coordination sphere of the ions.

关键词： chemiluminescence electrochemiluminescence cut-off fdter method lanthanide rare earths

Effective regulation of electronic structures and luminescence properties of LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):dy^(3+)phosphors by tetrahedral substitution

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Journal of Rare Earths 2023年第5期41卷 673-681,I0002页

作者： Yuanyuan Zhang Lefu mei Haikun Liu Sergey m.Aksenov Dina V.Deyneko Deliang Chen School of materials Sciences and Technology Dongguan University of TechnologyDongguan 523808China School of materials Science and Engineering Xi'an Jiaotong UniversityXi'an 710049China Beijing Key Laboratory of materials Utilization of Nonmetallic minerals and Solid Wastes National Laboratory of Mineral MaterialsSchool of Materials Sciences and TechnologyChina University of GeosciencesBeijing 100083China Department of Energy and Chemical Engineering Dongguan University of TechnologyDongguan 523808China Laboratory of Arctic mineralogy and material Sciences Kola Science CentreRussian Academy of Sciences14 Fersman StrApatity184209Russia Laboratory of Nature-Inspired Technologies and Environmental Safety of the Arctic Kola Science CentreRussian Academy of SciencesApatity18420 Russia Department of Chemistry Lomonosov Moscow State UniversityMoscow119991Russia School of materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China

A series of dy^(3+)-activated phosphors with the general formula LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):dy^(3+)(0≤x≤3)characterized by an apatite-type structure were successfully synthesized via a simple solid-state technique involving a partial substitution of[SiO_(4)]^(4-)with[GeO_(4)]^(4-)*** effects of homovalent[GeO_(4)]^(4-)-[SiO_(4)]^(4-)substitution on the crystal structure,electronic structure,luminescence properties and thermal performance of LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):dy^(3+)phosphors were studied in *** phases and microstructure were performed by using X-ray diffraction(XRD)Rietveld refinement method and scanning electron microscopy(SEm)*** substitution of smaller[SiO_(4)]^(4-)ions by larger[GeO_(4)]^(4-)ones makes their unit cell parameters increase gradually,and their band gaps *** photoluminescence spectra of LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):dy^(3+)(0≤x≤3)exhibit obvious emission peaks located at 477,573 and 675 nm within a visible wavelength region,resulting in an excellent white ***,the I573nm/I477nm values of LiGd_(9)(SiO_(4))6-x(GeO_(4))xO_(2):dy^(3+)(0≤x≤3)become larger with the partial substitution of[SiO_(4)]^(4-)by[GeO_(4)]^(4-),and their CIE chromaticity coordinates exhibit a yellow shift.

关键词： Apatite Structure substitution Electronic structure White emitting Rare earths

First-principles prediction of the magnetism of 4f rare-earth-metal-doped wurtzite zinc oxide

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Journal of Rare Earths 2014年第8期32卷 715-721页

作者： A.G.El Hachimi H.Zaari A.Benyoussef m.El Yadari A.El Kenz Laboratoire de magnétisme et Physique des Hautes Energies LMPHE (URAC 12) Département de Physique B.P.1014 Faculté des SciencesUniversité Mohammed V-Agdal Institut of Nanomaterials and Nanotechnology Hassan II Academy of Science and Technology Department of Science Moulay Ismail University Faculté Polydisciplinaire

Electronic structure and magnetic properties of wurtzite ZnO semiconductor doped with rare earth （RE=La, Ce, Pr, Pm, Nd, Sm, Eu, Gd, Tb, dy, Ho, Er, Tm and Yb） atoms were studied using spin-polarized density functional theory based on the full-potential linear augmented plane wave （FP-LAPW） method as implemented in the Wien2k code. In this approach the generalized gradient approximation （GGA） was used for the exchange-correlation （XC） potential. Our results showed that the substitution of RE ions in ZnO induced spins polarized localized states in the band gap. moreover, the studied DmSs compounds retained half metallicity at dopant concentration x=0.625%for most of the studied elements, with 100%spin polarization at the Fermi level （EF）. The total magnetic moments of these compounds existed due to RE 4f states present at EF, while small induced magnetic moments existed on other non-magnetic atoms as well. Finally, the energy difference between far and near configurations was investigated. It was found that the room temperature ferromagnetism was possible for RE-doped ZnO at near configuration. Since the RE-RE separation was long enough （far configuration） for magnetic coupling, the system became paramagnetic or antiferromagnetic ground state.

关键词： ZnO rare earths ferromagnetism DmS electronic structure magnetic properties half-metallic RE-doped ZnO FP-LAPW method density functional theory

Effect of chemical composition on zircon radiation damage dating:Implications for low-temperature thermochronology

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Geoscience Frontiers 2023年第6期14卷 368-379页

作者： mingpu Fan Xiaoming Liu Shengsi Sun Yunpeng Dong John C.Ayers m.Santosh State Key Laboratory of Continental dynamics Department of GeologyNorthwest UniversityXi’an 710069China Vanderbilt University Department of Earth&Environmental SciencesPMB 3518052301 Vanderbilt PlaceNashvilleTN 37235-1805USA School of Earth Science and Resources China University of GeosciencesBeijing 100083China Department of Earth Science University of AdelaideAdelaideSA 5005Australia Yonsei Frontier Lab Yonsei UniversitySeoul 03722Republic of Korea

Zircon radiation damage dating is a low-temperature thermochronological method that can reveal the cooling histories of magmatic intrusions and discriminate sedimentary provenance in combination with other dating *** method has broad application prospects because of its advantages of nondestructive,high efficiency,and capable of double(or multiple)dating,involving only multiple measurements by Raman spectrometer and laser ablation-inductively coupled plasma-mass ***,several factors,such as zircon chemical composition and the non-uniformity of radiation damage annealing kinetics,can cause poor precision when using this method and thus restricts its wide *** study examined the effect of chemical composition(P,Ti,dy,Th,U,and Hf)on Raman spectra using synthetic zircon crystals grown in a lithium-molybdate *** results show that the full width at half-maximum(FWHm)of the v_(3)(SiO_(4))band has positive linear correlations with the concentrations of P,Ti,dy,Th,and U in decreasing order of influence,while the FWHm is unaffected by Hf at concentrations10 wt.%.Furthermore,the Raman shift is negatively correlated with Th,U,and dy concentrations,positively correlated with Hf,and shows no obvious correlation with Ti and ***,our study shows that chemical composition is a non-ignorable factor for calculating zircon radiation damage age using Raman spectroscopy,especially for zircon with relatively high concentrations of P,rare earth elements(REEs),Th,U,and *** obtained multiple linear regression equation provides a potential means for estimating the FWHm at zero dose and implication for improving the dating precision of this *** addition,the observed effects of REEs,Th,U,and Hf on the Raman shift of the v_(3)(SiO_(4))band indicate that chemical composition in zircon might affect the estimation of the P-T conditions of geological processes when using entrapped zircon inclusions in host mi

关键词： Synthetic zircon Raman spectroscopy Chemical composition Radiation damage dating Cooling age

metathesis synthesis, characterization, spectral and photoactivity studies of Ln_(2/3)moO_4(Ln=La, Pr, Nd, Sm, Eu, Gd, Tb, dy, Er and Y)

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Journal of Rare Earths 2015年第8期33卷 837-845页

作者： Radha Velchuri Suresh Palla G.Ravi Naveen Kumar Veldurthi J.R.Reddy m.Vithal Department of Chemistry Osmania University

Rare earth ortho-oxomolybdates of composition Ln2/amoO4 （Ln=La, Pr, Nd, Sm, Eu, Gd, Tb, dy, Er and Y） were prepared by metathesis reaction. All these materials were characterized by powder X-ray diffraction, Fourier transform-infrared spectroscopy （FT-IR） and UV-Vis diffuse reflectance spectra. The Rietveld analysis of all the samples was carried out to obtain the unit cell parameters and reliability factors. All the materials were crystallized in tetragonal lattice with I41/a space group. The infrared spectra of all the samples were characterized by bands due to moO42 units. The bandgap energies of all the samples were obtained from UV-Vis DRS spectra. The luminescence spectra of Ln2/3moO4 （Ln=Pr, Eu and dy） showed characteristic transitions of the rare earth ions. The visible light photocatalytic activity of all the samples was studied against degradation of methylene blue.

关键词： metathesis X-ray diffxaction IR spectroscopy UV-Vis spectroscopy photodegradation rare earths

Wettability of silicon carbide ceramic by Al_2O_3/dy_2O_3 and Al_2O_3/Yb_2O_3 systems

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Journal of Rare Earths 2013年第6期31卷 634-638页

作者： J.A.da Silva B.m.moreschi G.C.R.Garcia S.Ribeiro Department of materials Engineering (DEmAR) Engineering School of Lorena (EEL)Pólo Urbo IndustrialGleba AI6CP 11612608-970LorenaSPBrazil

Wettability is an important phenomenon in the liquid phase sintering of silicon carbide （SiC） ceramics. This work involved a study of the wetting of SiC ceramics by two oxide systems, Al2O3 /dy2O3 and Al2O3 /Yb2O3, which have so far not been studied for application in the sintering of SiC ceramics. Five mixtures of each system were prepared, with different compositions close to their respective eutectic ones. Samples of the mixtures were pressed into cylindrical specimens, which were placed on a SiC plate and subjected to temperatures above their melting points using a graphite resistance furnace. The behavior of the melted mixtures on the SiC plate was observed by means of an imaging system using a CCD camera and the sessile drop method was employed to determine the contact angle, the parameter that measures the degree of wettability. The results of variation in the contact angle as a function of temperature were plotted in graphic form which showed that the curves displayed a fast decline and good spreading. All the samples of the two systems presented final contact angles of 40o to 10o indicating their good wetting on SiC in the argon atmosphere. The melted/solidified area and interface between SiC and melted/solidified phase were evaluated by scanning electron microscopy （SEm） and their crystalline phases were identified by X-ray diffraction （DRX）. The DRX analysis showed that Al2O3 and RE2O3 reacted and formed the dy3Al5O12 （dyAg） and Yb3Al5O12 （YbAg） phases. The results indicated that the two systems had a promising potential as additives for the sintering of SiC ceramics.

关键词： liquid-phase sintering silicon carbide rare earth oxide wettability contact angle

Spectral change and far-red emission of mn^(2+)ions co-doped NaSrB_(5)O_(9):dy^(3+)luminescence material for plant growth LEDs

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Journal of Rare Earths 2022年第2期40卷 218-225,I0002页

作者： K.munirathnam Koduru mallikarjuna R.Vijaya P.C.Nagajyothi K.Ramakrishna Reddy m.Srinivas Department of Physics School of Applied SciencesREVA UniversityBengaluru560064India Department for management of Science and Technology Development Ton Due Thang UniversityHo Chi Minh CityVietnam Faculty of Applied Sciences Ton Due Thang UniversityHo Chi Minh CityVietnam Department of Physics Visvodaya Government Degree CollegeVenkatagiri524132India School of mechanical Engineering Yeungnam UniversityGyeongsan33541South Korea Department of Chemistry School of Applied SciencesREVA UniversityBengaluru560064India

Due to the characteristic emission of phosphors,phosphor-converted LEDs have been employed to provide the requisite light sources for indoor plant growth in the optical agricultural ***,we prepared a series of mn^(2+)co-doped NaSrB5 O9:dy^(3+)phosphors via a solid-state reaction *** phosphors have significant three-band emissions at 467 nm(blue region),606 nm(orange region),and765 nm(far-red region),ascribed to the^(4)F_(9/2)-^(6)H_(15/2)and 4 F9/2-6 H13/2 transitions of the dy^(3+)ions and the^(4)T_(1g)(G)-^(6)A_(1g)(S)spin-forbidden transition of the mn^(2+)ions,respectively,when excited by light of 376 nm(near-UV region).The co-dopant in the host material facilitates tunable photoluminescence(PL)due to energy transfer from the dy^(3+)ions to the mn^(2+)*** three emission peaks from the prepared phosphors well match with the absorption spectra of the photosynthesis pigments of plants,chlorophyll and phytochrome,which can absorb blue(400-500 nm),orange-red(550-700 nm),and infrared(IR)radiation,indicating that these phosphors have potential applications in the fabrication of plant-growth *** to the PL studies,the structure of the phosphors was determined by X-ray diffraction,refined by Rietveld method and chemically quantified by X-ray photoelectron spectroscopy.

关键词： Phosphors Refinement X-ray photoelectron spectroscopy Energy transfer Plant growth LEDs Rare earths

纳米复合Fe-R-O(R=Hf,Nd,dy)薄膜面内铁磁共振研究

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物理学报 2004年第7期53卷 2352-2356页

作者：杜军孙亮盛雯婷游彪鹿牧胡安 m.m.CorteReal J.Q.Xiao 南京大学物理系 Department of Physics and Astronomy

用反应溅射方法制备了Fe R O(R =Hf,Nd ,dy)薄膜 ,并在 4 0 0℃时对样品进行退火处理 ,x射线衍射和电子衍射结果显示纳米量级的Fe晶粒镶嵌在非晶氧化物基质中 .用面内铁磁共振技术仔细测量了样品的共振吸收谱 ,并分析了局域磁化强度ms ... 详细信息

用反应溅射方法制备了Fe R O(R =Hf,Nd ,dy)薄膜 ,并在 4 0 0℃时对样品进行退火处理 ,x射线衍射和电子衍射结果显示纳米量级的Fe晶粒镶嵌在非晶氧化物基质中 .用面内铁磁共振技术仔细测量了样品的共振吸收谱 ,并分析了局域磁化强度ms 与晶粒尺寸的关系 .制备态样品呈现出显著的面内单轴各向异性 ,退火后单轴各向异性显著减弱 ,取而代之的是较弱的磁晶各向异性 .利用公式 (ω γ) 2 =(Hres+HK) (Hres+HK +4πms)求出局域磁化强度ms,它随晶粒尺寸减小而减小 ,在晶粒尺寸为 5nm时仅约为Fe体材料饱和磁化强度的 30 % .局域磁化强度与根据Fe的体积百分比算出的体磁化强度相比偏小 ,并与晶粒尺寸的倒数呈线性关系 ,说明在晶粒表面存在较强的磁矩钉扎效应 .

关键词：铁磁共振局域磁化强度单轴各向异性磁晶各向异性纳米复合薄膜