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1.
Dragan Mihailovic 《Monatshefte für Chemie / Chemical Monthly》2003,134(2):137-147
Ferromagnetism in fullerene-based systems doped with metallocenes is reviewed. These compounds form a ferromagnetic state
by spin-coupling between π electrons on fullerene units, while the metallocene molecules do not contribute to the spin ordering.
One of these compounds has the highest critical temperature (19 K) for this class of compound. The magnetic properties of
these materials are very strongly dependent on the crystallization conditions.
Corresponding author. E-mail: Dragan.Mihailovic@ijs.si
Received September 4, 2002; accepted September 6, 2002 相似文献
2.
《Solid State Sciences》1999,1(6):381-393
The synthetic layered 1:1 phyllosilicate, Co2.3Al0.7Si1.3Al0.7O5(OH)4, and 2:1 phyllosilicates Co3Si4O10(OH)0.7F1.3, Co3Si4O10(OH)1.2F0.8(Co(CH3COO)2)0.24, Co3Si4O10(OH)1.3F0.7 (TAEAH)0.12 and Co3Si4O10(OH)1.3F0.7 (TAEAH)0.24 have been obtained under hydrothermal conditions at ca. 200 °C (TAEA : (tris-aminoethyl)-amine). The compounds are characterized by interplanar distances of 7.0, 9.5, 11.1, 13.3 and 14.3 Å, respectively. They show long range magnetic ordering below 16 K, characterized by positive Weiss constants, imaginary component in the ac-susceptibility, spontaneous magnetisation in small applied field and coercive fields in the range 400 to 700 Oe. The magnetisation in field of 3 Tesla classifies them as 3D ferromagnet. 相似文献
3.
Dragan Mihailovic 《Monatshefte für Chemie / Chemical Monthly》2003,87(1):137-147
Ferromagnetism in fullerene-based systems doped with metallocenes is reviewed. These compounds form a ferromagnetic state by spin-coupling between π electrons on fullerene units, while the metallocene molecules do not contribute to the spin ordering. One of these compounds has the highest critical temperature (19 K) for this class of compound. The magnetic properties of these materials are very strongly dependent on the crystallization conditions. 相似文献
4.
V. M. Novotortsev I. S. Zakharov A. V. Kochura S. F. Marenkin R. Laiho E. Lahderanta A. Lashkul A. G. Veresov A. V. Molchanov G. S. Yur’ev 《Russian Journal of Inorganic Chemistry》2006,51(10):1627-1631
InSb samples containing 0.22–1.42 wt % manganese were synthesized and identified. The unit cell parameter decreased as the manganese concentration increased. The samples contained microinclusions of manganese antimonides. Electrical and magnetic measurements showed two ferromagnetic phases (In1?x MnxSb solid solution with T c ~ 7 K and MnSb with T c ~ 580 K) and a ferrimagnetic phase (Mn2Sb). The samples had p-type conductivity with a charge carrier concentration of about 1020cm?3. The semiconductor conductivity was observed at low temperatures and changed to the metal conductivity with temperature elevation. 相似文献
5.
Urmimala Maitra Barun Das Nitesh Kumar Dr. Athinarayanan Sundaresan Prof. Dr. C. N. R. Rao 《Chemphyschem》2011,12(12):2322-2327
Gold nanoparticles with average diameters in the range 2.5–15 nm, prepared at the organic/aqueous interface by using tetrakis(hydroxymethyl)phosphonium chloride (THPC) as reducing agent, exhibit ferromagnetism whereby the saturation magnetization MS increases with decreasing diameter and varies linearly with the fraction of surface atoms. The value of MS is higher when the particles are present as a film instead of as a sol. Capping with strongly interacting ligands such as alkane thiols results in a higher MS value, which varies with the strength of the metal–sulfur bond. Ferromagnetism is also found in Pt and Ag nanoparticles prepared as sols, and the MS values vary as Pt>Au>Ag. A careful study of the temperature variation of the magnetization of Au nanoparticles, along with certain other observations, suggests that small bare nanoparticles of noble metals could indeed possess ferromagnetism, albeit weak, which is accentuated in the presence of capping agents, specially alkane thiols which form strong metal–sulfur bonds. 相似文献
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Miyajima K Nakajima A Yabushita S Knickelbein MB Kaya K 《Journal of the American Chemical Society》2004,126(41):13202-13203
A molecular beam of multilayer vanadium-benzene organometallic complexes Vn(C6H6)m was produced by a laser vaporization synthesis method. The magnetic moments of the complexes were measured by a molecular beam magnetic deflection technique, and were found to increase with the number of vanadium atoms in the cluster, showing that the unpaired electrons, which occupy the nonbonding dsigma orbitals localized on the metal atoms, couple ferromagnetically. These sandwich species represent a new class of one-dimensional molecular magnets in which the transition metal atoms are formally zerovalent. 相似文献
7.
Shahid Atiq Saadat A.Siddiqi Fazal Abbas Murtaza Saleem Shahid M. Ramay 《化学物理学报(中文版)》2013,26(4):457-461
Zn0.95-xAlxMn0.05O (x=0, 0.03, 0.05, and 0.07) dilute magnetic semiconductor materials have been synthesized by sol-gel auto-combustion technique. The effect of Al doping on the structural, electrical, and magnetic properties has been investigated. X-ray diffraction studies demonstrate the existence of single phase characteristic hexagonal wurtzite type crystal structure, similar to the host ZnO, in all the synthesized compositions. Although, the microscopic images revealed that the grains were clustered, yet some individual grains could be seen to have hexagonal texture. Electrical resistivity was observed to decrease with the rise of temperature up to 450 oC, depicting the characteristic semiconductor behavior. Room temperature ferromagnetic behavior was observed in all the compositions. The value of saturation magnetization increased with the increase of Al concentration in ZnMnO system referred to the gradual enhancement of free carriers. 相似文献
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Coronado E Gómez-García CJ Nuez A Romero FM Rusanov E Stoeckli-Evans H 《Inorganic chemistry》2002,41(18):4615-4617
The combination of hexacyanoferrate(III) anions, [Fe(CN)(6)](3)(-), with nickel(II) complexes derived from the chiral ligand trans-cyclohexane-1,2-diamine (trans-chxn) affords the enantiopure layered compounds [Ni(trans-(1S,2S)-chxn)(2)](3)[Fe(CN)(6)](2).2H(2)O (1) and [Ni(trans-(1R,2R)-chxn)(2)](3)[Fe(CN)(6)](2).2H(2)O (2). These chiral systems behave as ferromagnets (T(c) = 13.8 K) with a relatively high coercive field (H(c) = 0.17 T) at 2 K. They also exhibit an unusual magnetic behavior at low temperatures that has been attributed to the dynamics of the magnetic domains in the ordered phase. 相似文献
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O. N. Pashkova A. D. Izotov V. P. Sanygin A. V. Filatov 《Russian Journal of Inorganic Chemistry》2014,59(11):1324-1327
A polycrystalline sample of composition GaSb + 2% Mn was prepared by melt quenching. Manganese substitutes for gallium positions to form limited solid solution Ga1 ? x Mn x Sb, as shown by X-ray powder diffraction and SEM, but most manganese is consumed in the formation of magnetically ordered Mn1.1Sb inclusions having the Curie point T C ≈ 560 K, as shown by magnetic studies. 相似文献
12.
SUN Qiushi WANG Xiaofeng LI Benxian WU Yunpeng ZHANG Ziqing ZHANG Xinyang ZHAO Xudong LIU Xiaoyang 《高等学校化学研究》2018,34(3):344-349
Ferromagnetism of pure carbon-based materials has been widely researched for several years. In therocially and experimentally, semi-hydrogenation graphene sheets exhibit ferromagnitism, which is related to the degree of hydrogenation. Here we reported the controllable hydrogenation of graphene using ball-milling method with acetic acid as hydrogenating agent. The hydrogenation graphene sheets were characterized by means of transmission electron microscopy(TEM), Raman spectroscopy and X-ray photoelectron spectroscopy, and magnetic measurement. The relusts of Raman spectroscopy demonstrate that the relative intensity of D band increases with the hydrogenation degree. The resluts of magnetic meansurement indicate the maximal magnetic moment of 0.274 A·m2/kg at 2 K for semi-hydrogenation graphene. 相似文献
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Xiaojun Zhang Prof. Dr. Hui Xu 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2024,136(10):e202317597
Optoelectronic cluster materials emerge rapidly in recent years especially for light-emitting devices, owing to their 100 % exciton harvesting and unique organic–inorganic hybrid structures with tunable excited-state characteristics for thermally activated delayed fluorescence and/or phosphorescence and inheritable photo- and thermo-stability. However, for efficient electroluminescence, excited-state compositions of cluster emitters should be tuned through ligand engineering to enhance ligand-centered radiative components and reduce cluster-centered quenching states. Nonetheless, the balance of optoelectronic properties requires delicate and controllable ligand functionalization. On the other hand, in addition to balancing carrier fluxes, it showed that device engineering, especially host matrixes and interfacial optimization, can not only alleviate triplet quenching, but also modify processing and passivate defects. As consequence, the record external quantum efficiencies of cluster light-emitting diodes already reached ≈30 %. Herein, we overview recent progress of electroluminescent cluster materials and discuss their structure–property relationships, which would inspire the continuous efforts making cluster light-emitting diodes competent as the new generation of displays and lighting sources. 相似文献
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Bruno Therrien Wee Han Ang Frédéric Chérioux Ludovic Vieille-Petit Lucienne Juillerat-Jeanneret Georg Süss-Fink Paul J. Dyson 《Journal of Cluster Science》2007,18(3):741-752
Abstract The in vitro activity of a series of ruthenium clusters, [(η6-C6H6)(η6-C6Me6)2Ru3(μ-H)3(μ3-O)][BF4], [(η6-C6H6)(η6-1,4-iPrC6H4Me)(η6-C6Me6)Ru3(μ-H)3(μ3-O)][BF4], [(η6-C6H6)4Ru4(μ-H)4][BF4]2, [(η6-C6H5Me)4Ru4(μ-H)4][BF4]2 and [(η6-C6H6)4Ru4(μ-H)3(μ-OH)][Cl]2, has been evaluated against A2780 and A2780cisR ovarian carcinoma cell lines. Both triruthenium clusters are very active
compared to ruthenium compounds in general, whereas the tetraruthenium clusters do not display significant cytotoxicities.
Since the triruthenium clusters are known to form supramolecular interactions with arenes and other functions, it is possible
that such interactions are also important with respect to their mode of biological activity. The X-ray structure analysis
of [(η6-C6H5Me)4Ru4(μ-H)4][PF6]2 is also reported.
Graphical Abstract The in vitro activity of a series of ruthenium clusters has been evaluated against A2780 and A2780cisR ovarian carcinoma cell lines and
their activity compared to cisplatin. The triruthenium clusters are very active, while the tetraruthenium clusters do not
display significant cytotoxicities.
Dedicated to Professor Dieter Fenske on the occasion of his 65th birthday anniversary 相似文献
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《Solid State Sciences》2007,9(7):574-579
This paper reports the specific conditions used in the preparation of the dimorphic phases of HoCrO4 oxide. The scheelite form has been obtained from the room pressure stable HoCrO4–zircon heated at 823 K at 40 kbar. The structures of both the polytypes have been refined from X-ray powder diffraction data using the Rietveld method. The zircon type of HoCrO4 oxide crystallizes with tetragonal symmetry, S.G. I41/amd and lattice parameters a = 7.119(10) and c = 6.2557(5) Å; while the scheelite–HoCrO4 derivative shows tetragonal symmetry, S.G. I41/a and lattice parameters a = 5.0017(1) and c = 11.2664(2) Å. Magnetic susceptibility measurements show that both zircon and scheelite forms of HoCrO4 oxide present a very different magnetic behaviour at low temperatures. The zircon form behaves as a ferromagnet with a Curie temperature of 17.6 K, while the scheelite form is antiferromagnetic with a Néel temperature of 7.6 K. A metamagnetic transition for the scheelite form with a critical field of 1 T at 2 K has been also observed. The changes in the sign of the interactions have been also analyzed by considering the possible super-exchange mechanisms and the differences found in the Ho–O–Cr distances and bond angles in going from zircon to scheelite structural type. 相似文献
20.
High-temperature hydrolysis of Zn(II) and Mn(II) alkoxides in a high boiling point solvent in the presence of surfactants was used to prepare surfactant-coated Zn(1-x)Mn(x)O nanocrystals with average size of 5.5 nm and x = 0.04 +/- 0.03. The magnetic properties of the nanocrystals were measured both for isolated particles diluted in a hydrocarbon matrix and for a nanocrystal powder. Nanocrystals of manganese oxide and ZnO coated with manganese oxide were prepared for comparison to the Zn(1-x)Mn(x)O nanocrystals. We find that the manganese ions primarily substitute zinc ions in the hexagonal ZnO lattice, and part of them are ferromagnetically coupled up to room temperature even in isolated noninteracting nanocrystals. The rest of the ions are magnetically disordered or uncoupled. Surprisingly, these small Zn(1-x)Mn(x)O nanocrystals poses relatively large low-temperature magnetic coercivity and relatively high blocking temperature in the isolated form, which indicate large magnetic anisotropy. In the nanocrystal powder the coercive field decreased significantly. This study highlights the advantages of working with noninteracting single domain particles of these intriguing materials. 相似文献