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Original Title
Uber die Hektoboridphasen der Lanthaniden und Aktiniden
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Journal Article
Journal
Journal of the Less-Common Metals; v. 26(1); p. 99-104
Country of publication
CERIUM BORIDES, DYSPROSIUM BORIDES, ERBIUM BORIDES, EUROPIUM BORIDES, GADOLINIUM BORIDES, HOLMIUM BORIDES, KNOOP HARDNESS, LANTHANUM BORIDES, LATTICE PARAMETERS, LUTETIUM BORIDES, MILLER INDICES, NEODYMIUM BORIDES, PLUTONIUM BORIDES, PRASEODYMIUM BORIDES, SAMARIUM BORIDES, STABILITY, TERBIUM BORIDES, THORIUM BORIDES, X-RAY DIFFRACTION, YTTERBIUM BORIDES, YTTRIUM BORIDES
ACTINIDE COMPOUNDS, BORIDES, CERIUM COMPOUNDS, COHERENT SCATTERING, DIFFRACTION, DYSPROSIUM COMPOUNDS, ERBIUM COMPOUNDS, EUROPIUM COMPOUNDS, GADOLINIUM COMPOUNDS, HOLMIUM COMPOUNDS, LANTHANUM COMPOUNDS, LUTETIUM COMPOUNDS, NEODYMIUM COMPOUNDS, PLUTONIUM COMPOUNDS, PRASEODYMIUM COMPOUNDS, RARE EARTH COMPOUNDS, SAMARIUM COMPOUNDS, SCATTERING, TERBIUM COMPOUNDS, THORIUM COMPOUNDS, TRANSITION ELEMENT COMPOUNDS, TRANSURANIUM COMPOUNDS, YTTERBIUM COMPOUNDS, YTTRIUM COMPOUNDS
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AbstractAbstract
[en] Exchange and crystal fields (CF) acting on R3+ ions in R2Fe14B were investigated by means of inelastic magnetic neutron scattering. Experimental data for R=Pr, Nd, Gd, Tb, Dy, Ho, Er, and Tm are reviewed. Molecular fields H acting on R ions are calculated using neutron-scattering data for the CF models proposed earlier for these compounds based on single-crystal magnetization measurements. For Gd2Fe14B the molecular field acting on the Gd3+ ions was directly determined by inelastic neutron scattering as 2μBHm/kB = 435 K
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AbstractAbstract
[en] For a group of s-, p-, and d-metal diborides (MB2, where M = Mg, Al, Sc, Ti, V, Y, Zr, Nb, or Ta), variations in the cohesive energy and the formation energy in the presence of cation vacancies (MB2 → M0.75B2), as well as the formation energy of cation-site vacancies, are analyzed using the FLMTO-GGA full-potential approach. The cationic nonstoichiometry for MB2 phases is achievable only when they are prepared under nonequilibrium conditions
[ru]
Для группы диборидов s-, p-, d-металлов (МВ2, где М = Mg, Al, Sc, Ti, V, Y, Zr, Nb и Та) в рамках полнопотенциального метода FLMTO-GGA выполнен анализ изменений их энергий когезии и энергий формирования в присутствии вакансий по катионной подрешетке (МВ2 → М0.75B2), а также энергий образования катионных вакансий. Установлено, что катионная нестехиометрия для МВ2-фаз может быть достигнута лишь при неравновесных условиях их полученияOriginal Title
Vliyanie metallicheskikh vakansij na ehnergeticheskie kharakteristiki diboridov s-, p-, d-metallov
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Source
21 refs., 2 figs., 4 tabs.
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Journal Article
Journal
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ALKALINE EARTH METAL COMPOUNDS, ALUMINIUM COMPOUNDS, BORIDES, BORON COMPOUNDS, CHARGED PARTICLES, CRYSTAL DEFECTS, CRYSTAL STRUCTURE, IONS, MAGNESIUM COMPOUNDS, NIOBIUM COMPOUNDS, POINT DEFECTS, REFRACTORY METAL COMPOUNDS, SCANDIUM COMPOUNDS, TANTALUM COMPOUNDS, TITANIUM COMPOUNDS, TRANSITION ELEMENT COMPOUNDS, VANADIUM COMPOUNDS, YTTRIUM COMPOUNDS, ZIRCONIUM COMPOUNDS
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Brupbacher, J.M.; Christodoulou, L.; Nagle, D.C.
Martin Marietta Corp., Bethesda, MD1990
Martin Marietta Corp., Bethesda, MD1990
AbstractAbstract
[en] This paper describes a method for the formation of complex boride whiskers within a final metal matrix. The complex boride comprises boron and at least two of the elements selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo and W
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Secondary Subject
Source
10 Apr 1990; 17 Feb 1988; vp; US PATENT DOCUMENT 491590/A/; Patent and Trademark Office, Box 9, Washington, DC 20232 (USA); ?: 17 Feb 1988
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Patent
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AbstractAbstract
[en] Magnetic and structural behaviour and phase relationships of materials of composition R3Ni7B2 (R = Nd-Lu) were investigated. Detailed X-ray analysis yields that two hexagonal structures are encountered. For the heavy rare earth (Gd-Lu) the compounds crystallize in the CeNi3 structure. The space group is P63/mmc and each unit cell contains two formula units. The R3Ni7B2 where R = Nd-Sm (including Yb3Ni7B2) crystallize in the CeCo4B structure. The space group is P6/mmm and each unit cell contains one formula unit. The detailed crystal structures are discussed. The magnetic measurements show that Yb3Ni7B2 and Lu3Ni7B2 are Pauli paramagnetic. Sm3Ni7B2 is ferromagnetically ordered with a huge intrinsic magnetic hardness. The magnetization at the coercive field at low temperatures is extremely time dependent. The R3Ni7B2 which crystallize in CeNi3 structure are antiferromagnetic at low temperatures. All Mossbauer and magnetization experimental results can be explained assuming an antiferromagnetic exchange interaction in both 2(c) and 4(f) crystallographic sites and a ferromagnetic interaction between these sites. (author)
Record Type
Journal Article
Journal
Journal of Physics and Chemistry of Solids; ISSN 0022-3697;
; v. 44(1); p. 43-48

Country of publication
CRYSTAL STRUCTURE, DYSPROSIUM BORIDES, ERBIUM BORIDES, EUROPIUM BORIDES, GADOLINIUM BORIDES, HOLMIUM BORIDES, LATTICE PARAMETERS, LUTETIUM BORIDES, MAGNETIC SUSCEPTIBILITY, MAGNETIZATION, MOESSBAUER EFFECT, NEODYMIUM BORIDES, NICKEL BORIDES, SAMARIUM BORIDES, TEMPERATURE DEPENDENCE, TERBIUM BORIDES, THULIUM BORIDES, X-RAY DIFFRACTION, YTTERBIUM BORIDES
BORIDES, BORON COMPOUNDS, COHERENT SCATTERING, DIFFRACTION, DYSPROSIUM COMPOUNDS, ERBIUM COMPOUNDS, EUROPIUM COMPOUNDS, GADOLINIUM COMPOUNDS, HOLMIUM COMPOUNDS, LUTETIUM COMPOUNDS, MAGNETIC MOMENTS, MAGNETIC PROPERTIES, NEODYMIUM COMPOUNDS, NICKEL COMPOUNDS, PHYSICAL PROPERTIES, RARE EARTH COMPOUNDS, SAMARIUM COMPOUNDS, SCATTERING, TERBIUM COMPOUNDS, THULIUM COMPOUNDS, TRANSITION ELEMENT COMPOUNDS, YTTERBIUM COMPOUNDS
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Yang, K.N.
California Univ., San Diego (USA)1985
California Univ., San Diego (USA)1985
AbstractAbstract
[en] An investigation of the interplay between long-range magnetic order and superconductivity in pseudoternary Ho(Rh/sub 1-x/Ir/sub x/)4B4 and Dy(Rh/sub 1-x/Ir/sub x/)4B4 systems was carried out by means of low temperature specific heat measurements. The properties of the intermediate valent compounds CeT3B2 and UT3B2 (T = CO, Ru, Rh, and Ir), as well as the behavior of superconductivity and ferromagnetism in pseudoternary Ce(Ru/sub 1-x/Rh/sub x/)3B2 compounds, were characterized by low temperature specific heat, electrical resistivity, and magnetic measurements. A low temperature phase diagram vs alloy composition was determined for Ho(Rh/sub 1-x/Ir/sub x/)4B4. The specific heat features associated with long-range ordering of the Ho+3 magnetic moments suggest mean field theory ferromagnetism for x less than or equal to 0.2. Antiferromagnetic ordering was observed for x greater than or equal to 0.2 and antiferromagnetic spin wave behavior was found for the ordered Ho+3 moments for x greater than or equal to 0.5. Unusual magnetic ordering occurs for 0.275 less than or equal to x less than or equal to 0.4 including two distinct magnetic transitions. The compound CeRh3B2 exhibits ferromagnetic ordering for T less than or equal to 113 K with a saturation magnetic moment 0.37 μ/sub B/ per formula unit, while CeRu3B2 exhibits superconductivity below 0.68 K. Values of the electronic specific heat coefficient γ for the compounds range from 9.7 mJ/mol-K2 for CeCo3B2 to 64 mJ/mol-K2 for UIr3B2. A phase diagram of the transition temperatures vs alloy composition was determined for Ce(Ru/sub 1-x/Rh/sub x/)3B2. Superconductivity of CeRu3B2 disappears for Rh substitution x greater than or equal to 0.38
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Source
1985; 159 p; University Microfilms Order No. 86-03,829; Thesis (Ph. D.).
Record Type
Report
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Thesis/Dissertation
Country of publication
ACTINIDE COMPOUNDS, BORIDES, BORON COMPOUNDS, CERIUM COMPOUNDS, COBALT COMPOUNDS, DIAGRAMS, DYSPROSIUM COMPOUNDS, ELECTRIC CONDUCTIVITY, ELECTRICAL PROPERTIES, HOLMIUM COMPOUNDS, INFORMATION, IRIDIUM COMPOUNDS, PHYSICAL PROPERTIES, RARE EARTH COMPOUNDS, RHODIUM COMPOUNDS, RUTHENIUM COMPOUNDS, TRANSITION ELEMENT COMPOUNDS, URANIUM COMPOUNDS
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Synthesis, characterization and investigation of thermoelectric properties of selected metal borides
Stober, Frederick
Technische Univ. Darmstadt (Germany). Fachbereich Chemie2012
Technische Univ. Darmstadt (Germany). Fachbereich Chemie2012
AbstractAbstract
[en] The present work deals with the high-temperature thermoelectric properties of transition metal [eg V, Cr, Mn, Ni, Cu] and lanthanide [e.g. Sc, Y, Gd, Er, Dy]-borides. In particular, intercalation compounds of beta-rhombohedral boron, compounds of the type MB_6_6, dodecaborides and hexaborides were examined. In the case of intercalation compounds of beta-rhombohedral boron it was found that the incorporation of metals such as Sc, Mn or Cu result in favorable thermoelectric properties. The reason is most likely the preferred occupation of the metal position M2 instead of M4. Composites, for example, DyB_6_6-DyB_1_2 show high electrical conductivities, high Seebeck effects at high temperatures due to the presence of DyB_1_2 and low thermal conductivities as a result of the DyB_6_6 matrix. At 1100K the composite DyB_6_6-DyB_1_2 shows a ZT value of 0.55, thus exceeding the ZT of boron carbide (B_1_3C_2) at this temperature which is considered the best p-type boride material. A composite of ErB_1_2-ErB_4-ErB_2 has negative Seebeck coefficients and shows a ZT value of 0.5 at 840K. Furthermore, the structure of tetragonal Scandiumdodecaboride ScB_1_2 was solved on the basis of synchrotron data from a crystalline powder, after it has been debated for decades but never fully resolved.
Original Title
Synthese, Charakterisierung und Untersuchung thermoelektrischer Eigenschaften ausgewaehlter Metallboride
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Source
4 Jun 2012; 197 p; Available from: http://tuprints.ulb.tu-darmstadt.de/3000/1/Dr_Arbeit_F.Stober_tuprints_corr2.pdf; Diss. (Dr.-Ing.)
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Miscellaneous
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Thesis/Dissertation
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CHROMIUM BORIDES, CLATHRATES, COPPER BORIDES, DYSPROSIUM BORIDES, ELECTRIC CONDUCTIVITY, ERBIUM BORIDES, GADOLINIUM BORIDES, MANGANESE BORIDES, NICKEL BORIDES, SCANDIUM BORIDES, SEEBECK EFFECT, SYNTHESIS, THERMAL CONDUCTIVITY, THERMOELECTRIC PROPERTIES, THULIUM BORIDES, VANADIUM BORIDES, YTTRIUM BORIDES
BORIDES, BORON COMPOUNDS, CHROMIUM COMPOUNDS, COPPER COMPOUNDS, DYSPROSIUM COMPOUNDS, ELECTRICAL PROPERTIES, ERBIUM COMPOUNDS, GADOLINIUM COMPOUNDS, MANGANESE COMPOUNDS, NICKEL COMPOUNDS, PHYSICAL PROPERTIES, RARE EARTH COMPOUNDS, SCANDIUM COMPOUNDS, THERMODYNAMIC PROPERTIES, THULIUM COMPOUNDS, TRANSITION ELEMENT COMPOUNDS, VANADIUM COMPOUNDS, YTTRIUM COMPOUNDS
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AbstractAbstract
[en] We have performed accurate ab initio total energy calculations using the full-potential linearized augmented plane-wave (FP-LAPW) method with the generalized gradient approximation (GGA) for the exchange-correlation potential to systematically investigate elastic properties of 18 stable, metastable and hypothetical hexagonal (AlB2-like) metal diborides MB2, where M = Na, Be, Mg, Ca, Al, Sc, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Ag and Au. For monocrystalline MB2, the optimized lattice parameters, independent elastic constants (Cij), bulk moduli (B) and shear moduli (G) are obtained and analyzed in comparison with the available theoretical and experimental data. For the first time, numerical estimates of a set of elastic parameters of the polycrystalline MB2 ceramics (in the framework of the Voigt-Reuss-Hill approximation), namely bulk and shear moduli, compressibility (β), Young's modulus (Y), Poisson's ratio (ν) and Lame coefficients (μ, λ), are performed.
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Source
S0953-8984(08)81031-4; Available from http://dx.doi.org/10.1088/0953-8984/20/41/415218; Country of input: International Atomic Energy Agency (IAEA)
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Journal Article
Journal
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ALUMINIUM BORIDES, BERYLLIUM BORIDES, CALCIUM BORIDES, CERAMICS, CHROMIUM BORIDES, COMPARATIVE EVALUATIONS, COMPRESSIBILITY, CORRELATIONS, ELASTICITY, GOLD COMPOUNDS, HAFNIUM BORIDES, LATTICE PARAMETERS, MAGNESIUM BORIDES, MOLYBDENUM BORIDES, NIOBIUM BORIDES, POLYCRYSTALS, POTENTIALS, SCANDIUM BORIDES, SILVER COMPOUNDS, SODIUM BORIDES, TANTALUM BORIDES, TITANIUM BORIDES, TUNGSTEN BORIDES, VANADIUM BORIDES, WAVE PROPAGATION, YOUNG MODULUS, YTTRIUM BORIDES, ZIRCONIUM BORIDES
ALKALI METAL COMPOUNDS, ALKALINE EARTH METAL COMPOUNDS, ALUMINIUM COMPOUNDS, BERYLLIUM COMPOUNDS, BORIDES, BORON COMPOUNDS, CALCIUM COMPOUNDS, CHROMIUM COMPOUNDS, CRYSTALS, EVALUATION, HAFNIUM COMPOUNDS, MAGNESIUM COMPOUNDS, MECHANICAL PROPERTIES, MOLYBDENUM COMPOUNDS, NIOBIUM COMPOUNDS, REFRACTORY METAL COMPOUNDS, SCANDIUM COMPOUNDS, SODIUM COMPOUNDS, TANTALUM COMPOUNDS, TITANIUM COMPOUNDS, TRANSITION ELEMENT COMPOUNDS, TUNGSTEN COMPOUNDS, VANADIUM COMPOUNDS, YTTRIUM COMPOUNDS, ZIRCONIUM COMPOUNDS
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AbstractAbstract
[en] Borides Ln2Ni15B9, where Ln=Y, Tb, Dy, Er, Tm, Yb, Lu, have been prepared for the first time. Their structure belonging to Ho2Ni15B9 type is ascertained by the method of X-ray analysis
Original Title
Novye boridy redkozemel'nykh metallov so strukturoj tipa Ho2Ni15B9
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Record Type
Journal Article
Journal
Izvestiya Akademii Nauk SSSR, Neorganicheskie Materialy; ISSN 0002-337X;
; CODEN IVNMA; v. 27(3); p. 506-508

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AbstractAbstract
[en] Powder samples and single crystals of the Ti9M2Ru18B8 (Cr, Mn, Co, Ni, Cu, Zn) phases were synthesized from the elements and characterized by powder and single-crystal X-ray diffraction as well as energy-dispersive X-ray analysis. The new phases are all isotypic and crystallize in the tetragonal system as substitutional variants of the Zn11Rh18B8-type structure (space group P4/mbm, no. 127). M2 dumbbells are observed and interconnect to each other along the [001] direction to build ''ladders''. The M-M dumbbell distances vary from 2.48 to 2.50 A and the distances between two dumbbells (M2.. M2) are all close to 2.97 A, whereas the chains are well separated from each other by distances of at least 11.20 A. A strong variation of the unit cell volume with increasing valence electron count is observed in the series. According to the results of tight-binding electronic structure calculations, Ru-B and Ti-Ru contacts are responsible for the structural stability of these phases. The strength of the M-M and M-Ru interactions decreases with increasing valence electron count in the series. Non vanishing density of states at the Fermi level indicates metallic character for all phases. (orig.)
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ECSSC XII: 12. European conference on solid state chemistry; Muenster (Germany); 20-23 Sep 2009; 29 refs.
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Journal Article
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Conference
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