Crystal Engineering最新文献_第4页

On the interrelation between the microscopic and macroscopic properties of materials 论材料微观与宏观性能的相互关系

Crystal Engineering Pub Date : 2002-09-01 DOI: 10.1016/S1463-0184(02)00025-4

Anatolii Ya Gubenko

引用次数: 0

Structural determination of physical properties in cuprates 铜酸盐物理性质的结构测定

Crystal Engineering Pub Date : 2002-09-01 DOI: 10.1016/S1463-0184(02)00031-X

G.J. Babonas , R. Szymczak , M. Baran , A. Reza , V. Maltsev , J. Sabataityte , S. Dyeyev

{"title":"Structural determination of physical properties in cuprates","authors":"G.J. Babonas , R. Szymczak , M. Baran , A. Reza , V. Maltsev , J. Sabataityte , S. Dyeyev","doi":"10.1016/S1463-0184(02)00031-X","DOIUrl":"10.1016/S1463-0184(02)00031-X","url":null,"abstract":"<div>Recently, the crystal structure of synthetic and natural Cu-O compounds was analyzed in the unified classification scheme. Structural units of cuprates as salts of hypothetical copper acids were distinguished and assumed to be responsible for characteristic physical properties of these Cu-O compounds. In this work the optical and magnetic properties were studied in a series of synthetic and natural cuprates. The fine structure in the optical spectra of (M2Cu2O3)m(CuO2)n, CuGeO3, linarite PbCu(OH)2(SO4) and malachite Cu2(OH)2CO3 and other Cu-O compounds was correlated to the electronic excitations in particular structural units typical of cuprates. The temperature dependence of magnetic susceptibility was investigated on a series of Cu oxysalt minerals. The dimerization of magnetic moments was considered as a property, which was determined by the type of cuprate structural units. The observed relationship between the crystal structure and physical properties is useful in search of new magnetic materials.</div>","PeriodicalId":10766,"journal":{"name":"Crystal Engineering","volume":"5 3","pages":"Pages 209-216"},"PeriodicalIF":0.0,"publicationDate":"2002-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1463-0184(02)00031-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76797959","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

Synthesis and crystal structure of novel Ruddlesden–Popper strontium niobium oxynitrides 新型Ruddlesden-Popper锶铌氧氮化物的合成与晶体结构

Crystal Engineering Pub Date : 2002-09-01 DOI: 10.1016/S1463-0184(02)00059-X

G. Tobías , J. Oró-Solé , D. Beltrán-Porter , A. Fuertes

{"title":"Synthesis and crystal structure of novel Ruddlesden–Popper strontium niobium oxynitrides","authors":"G. Tobías , J. Oró-Solé , D. Beltrán-Porter , A. Fuertes","doi":"10.1016/S1463-0184(02)00059-X","DOIUrl":"10.1016/S1463-0184(02)00059-X","url":null,"abstract":"<div>The family (SrO)(SrNbO2-xN)n is the first example of Ruddlesden-Popper strontium niobium oxynitrides and provides layered structures to obtain mixed valence niobium compounds with a variety of oxidation states and transport properties. We have prepared members with n=1 (Sr2NbO3N) and n=2 (Sr3Nb2O5N2) by solid state reaction of Nb2O5 and SrCO3 at 900–1050 °C under ammonia flow. These compounds crystallize in the I4/mmm space group and show a range of anionic stoichiometry that together with the N/O ratio determines the formal oxidation state for niobium and therefore the resultant physical properties. Samples of the n=1 member show mixed valence Nb5+/Nb4+ and are paramagnetic and very resistive at room temperature. This behavior may be understood by considering electron localization due to N/O disorder.</div>","PeriodicalId":10766,"journal":{"name":"Crystal Engineering","volume":"5 3","pages":"Pages 479-485"},"PeriodicalIF":0.0,"publicationDate":"2002-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1463-0184(02)00059-X","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89128870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 14

Perovskite manganites: potential materials for magnetic cooling at or near room temperature 钙钛矿锰矿:在室温或接近室温下进行磁冷却的潜在材料

Crystal Engineering Pub Date : 2002-09-01 DOI: 10.1016/S1463-0184(02)00049-7

Y. Xu , M. Meier , P. Das , M.R. Koblischka , U. Hartmann

引用次数: 96

Structural study of electrochemically-synthesized Ag2Cu2O4. A novel oxide sensitive to irradiation 电化学合成Ag2Cu2O4的结构研究。一种对辐照敏感的新型氧化物

Crystal Engineering Pub Date : 2002-09-01 DOI: 10.1016/S1463-0184(02)00057-6

D. Munoz-Rojas, J. Fraxedas, J. Oró, P. Gómez-Romero, N. Casañ-Pastor

引用次数: 19

Highly photoconducting sillenite single crystals 高光导硅辉石单晶

Crystal Engineering Pub Date : 2002-09-01 DOI: 10.1016/S1463-0184(02)00038-2

J. Żmija , M.T. Borowiec , A. Majchrowski , H. Szymczak , T. Zayarnyuk

引用次数: 6

Growths of MgB2 thin films by pulsed laser deposition 脉冲激光沉积法制备MgB2薄膜

Crystal Engineering Pub Date : 2002-09-01 DOI: 10.1016/S1463-0184(02)00050-3

M. Ionescu, J. McKinnon, C. Cai, A. Li, K. Konstantinov, A.V. Pan, S.X. Dou

{"title":"Growths of MgB2 thin films by pulsed laser deposition","authors":"M. Ionescu, J. McKinnon, C. Cai, A. Li, K. Konstantinov, A.V. Pan, S.X. Dou","doi":"10.1016/S1463-0184(02)00050-3","DOIUrl":"10.1016/S1463-0184(02)00050-3","url":null,"abstract":"<div>The recent discovery of metallic-like superconductivity in bulk MgB2 material [1] opened a new class of possible applications in current transport, magnetic field devices and electronic devices. Fabrication of thin films in situ is essential in order to explore the device applications of this material, and in spite of a few reports [2], [3], [4], this still remains a challenge. The main reasons for this are the high vapour pressure of Mg even at low temperatures, and the high susceptibility of Mg to oxidation. A number of c-axis oriented MgB2 films were grown on Al2O3-R cut, and the stoichiometry of the films was measured by ICP as a function of deposition pressure and laser fluence. It was found that the relative concentration of Mg on the substrate varies considerably with pressure and laser fluence. A relative concentration of around 53 at% Mg, which is necessary in order to form stoichiometric MgB2 phase, can be obtain only in a narrow range of deposition pressures and laser fluences. The films obtain under these conditions were characterised by X-ray diffraction and magnetic moment in applied fields up to 9T.</div>","PeriodicalId":10766,"journal":{"name":"Crystal Engineering","volume":"5 3","pages":"Pages 391-400"},"PeriodicalIF":0.0,"publicationDate":"2002-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1463-0184(02)00050-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81453813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

A study of grain orientation of Alkali doped polycrystalline YBCO ceramics using an EBSD technique 用EBSD技术研究碱掺杂多晶YBCO陶瓷的取向

Crystal Engineering Pub Date : 2002-09-01 DOI: 10.1016/S1463-0184(02)00052-7

A Koblischka-Veneva , F Mücklich , M.R Koblischka

引用次数: 5

Processing effects on the microstructure observed during densification of the NTE-compound ZrW2O8 nte -化合物ZrW2O8致密化过程中工艺对显微组织的影响

Crystal Engineering Pub Date : 2002-09-01 DOI: 10.1016/S1463-0184(02)00058-8

C. De Meyer , L. Vandeperre , I. Van Driessche , E. Bruneel , S. Hoste

{"title":"Processing effects on the microstructure observed during densification of the NTE-compound ZrW2O8","authors":"C. De Meyer , L. Vandeperre , I. Van Driessche , E. Bruneel , S. Hoste","doi":"10.1016/S1463-0184(02)00058-8","DOIUrl":"10.1016/S1463-0184(02)00058-8","url":null,"abstract":"<div>The crystal structure of zirconium tungstate exhibits large isotropic negative thermal expansion. As a result, zirconium tungstate might find use in applications which require tailored thermal expansion properties. In this work, the sintering ability of commercially available ZrW2O8 and the reactive sintering of an oxide mixture was studied. The microstructure obtained when sintering oxide mixtures on porous alumina based refractory fibre-boards is characterised by large pores and clear grain boundaries, arising from a liquid phase sintering mechanism due to chemical interaction of the oxide mixture with the fibre-board. Although this interaction is avoided when using commercially available zirconium tungstate its sintering ability is very poor. When reactive sintering of oxide mixtures was performed in sealed quartz tubes in air, dense zirconium tungstate was obtained. The reactivity of the oxide mixtures using quartz tubes as support, is dependent on the homogeneity and particle size of the precursor oxide mixture.</div>","PeriodicalId":10766,"journal":{"name":"Crystal Engineering","volume":"5 3","pages":"Pages 469-478"},"PeriodicalIF":0.0,"publicationDate":"2002-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S1463-0184(02)00058-8","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89138921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 12

Morphology of nanoscaled LaMO3-particles (M=Mn, Fe, Co, Ni) derived by citrate precursors in aqueous and alcoholic solvents 柠檬酸盐前驱体在水和醇溶剂中衍生的纳米lamo3颗粒(M=Mn, Fe, Co, Ni)的形貌

Crystal Engineering Pub Date : 2002-09-01 DOI: 10.1016/S1463-0184(02)00029-1

E. Krupicka, A. Reller, A. Weidenkaff

引用次数: 30