摘要:

Stability of misfit layer chalcogenides (M.L.C.) is always governed by a charge transfer (C.T.) mechanism. A comparison between M.L.C. and parent intercalated layered binary systems shows comparable characteristics, which illustrate the role of electron donor for the MX part (or its corresponding A-intercalant species) towards the TX2acceptor part. In that way, intercalation chemistry within the vdW gap of multilayered TX2misfit derivatives is also considered. The donor character of the MX part, easy to understand when trivalent M cations are present, can be also assumed if a divalent M cation is partly substituted for a trivalent one, as revealed from precise electron microprobe analysis. Examples of M.L.C. with enlarged MX part (with mixed M+II, M+III) emphasize the reality of the C.T. This M-to-T donor effect necessarily controls the transport and intercalation properties.

ISSN:1058-725X    

DOI:10.1080/10587250008026108

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Electronic structures of transition metal intercalated IT-TiS2, MxTiS2, are studied by means of angle resolved photoemission, Ti 2p photoabsorption, 2p XPS, 2p resonance valence photoemission and ultraviolet inverse photoemission spectroscopy. Dispersions of the valence bands are noticeably modified from the host IT-TiS2. Several new features are interpreted and importance of the electron correlation and hybridization effects is confirmed.

ISSN:1058-725X    

DOI:10.1080/10587250008026109

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Neutron magnetic scattering of intercalation compounds FexTiS2has been measured systematically as a function of Fe concentrationx. In thex= 0.15 and 1/4 samples, so-called small-angle scattering was observed associated with a spin-glass transition. In thex= 1/2 sample, clear magnetic Bragg reflections were observed. The position of the magnetic peak with the smallestQnumber was not commensurate with the nuclear lattice-unit. The magnetic structure of Fe1/2TiS2was found not to be a simple ferromagnetic structure as was ever suggested but a long-period magnetic structure. In thex= 1/3 sample, broad magnetic diffuse peak whoseQnumber was also not commensurate with the nuclear lattice-unit was observed. The origin of the magnetism of Fe1/3TiS2, what is called a cluster-glass, seems the short-range ordered magnetic-clusters with a long-period magnetic structure.

ISSN:1058-725X    

DOI:10.1080/10587250008026110

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Low dimensional triangle magnetism was studied for transition metal intercalates of incommensurate misfit layer compounds (RS)x[M0.33(NbS2)2] (R = La, Ce, M = Fe, Mn). Magnetization measurements for the single crystals of the Fe intercalated compounds (RS)x[Fe0.33(NbS2)2] show the successive magnetic transition at 14 K and 22 K. The strong frustration appears between two transition temperatures as quasi two-dimensional antiferro-magnetic triangular Ising spin system. In contrast, the Mn compounds (RS)x[Mn0.33(NbS2)2] has very low transition temperature of 3.0 K due to the nature of quasi two-dimensional Heisenberg spin system.

ISSN:1058-725X    

DOI:10.1080/10587250008026111

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Magnetic and neutron studies are done about iron-intercalated titanium diselenide, FexTiSe2with 0<x≤0.5. A neutron diffraction measurement shows that Fe-atoms are located between neighboring selenium layers. Magnetic measurements show that FexTiSe2are spin glasses for 0. 15≤x≤0.22 and antiferromagnets for 0.25≤x≤0.5.T-xmagnetic phase diagram is determined. This diagram is slightly different from that determined by Huntley et al. The difference may be caused by a formation of Fe-clusters in their samples. Thex-dependence of the parameters of paramagnetic susceptibilities is determined.

ISSN:1058-725X    

DOI:10.1080/10587250008026112

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

Raman scattering spectra and magnetic susceptibility are measured in intercalation compounds FexNbS2(0.159≤x≤0.325). A strong modification of Raman spectra is observed in a sample withx=0.239 (∼ 0.25) which is accompanied by 2a× 2astructural change and antiferromagnetic ordering. Some correlations between magnetic ordering (antiferromagnetic or spin glass) and structural change are also discussed for wide range of Fe contentsx.

ISSN:1058-725X    

DOI:10.1080/10587250008026113

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

KCr5Se8has a TIV5S8-type structure, containing K ions in one-dimensional tunnels. Deintercalated samples of KxCr5Se8(0.32 ≤x≤ 0.93) were prepared by leaching method using Alc3/FeCl3aqueous solution. These samples showed a broad peak of magnetic susceptibility at ca. 130 K.57Fe-Mössbauer spectra of Kx(Cr0.9557Fe0.05)5Se8(x= 1.0, 0.49) showed a quadrupole doublet at 300 K. Magnetic sextets appeared at 4.2 K in both samples, indicative of magnetic ordering. The observed isomer shift indicated that the charge of Fe is +3 in both samples. It was proposed that Se2-was partially oxidized by the deintercalation.

ISSN:1058-725X    

DOI:10.1080/10587250008026114

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

We report on a PE study of the electronic structure of pristine TiSe2. The experimental data are compared with results of band-structure calculations. It is confirmed that TiSe2reveals semimetallic properties. For the first time rare-earth metals were attempted to be incorporatedin situinto TiSe2. It is found that divalent Eu can be easy intercalated, whereas deposition of trivalent Gd leads to strong interfacial reactions. The electronic structure of the Eu-intercalation compound cannot be simply described within a rigid-band approach assuming charge transfer from Eu to unoccupied Tidstates. In a more elaborated approach hybridization phenomena have to be taken into consideration.

ISSN:1058-725X    

DOI:10.1080/10587250008026115

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

The microscopic state of the positively charged light particle in the transition metal dichalcogenide 2H-NbSe2was studied using the muon spin relaxation method (μ+SR) and muon level crossing resonance method (μ-LCR). Muons are expected to stay at interlayer position and behaves as a hydrogen like intercalant. We discuss the relation between conduction electron properties and the muon's behavior.

ISSN:1058-725X    

DOI:10.1080/10587250008026116

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor

摘要:

From the resistivity measurements of 3d metal intercalates MxTiS2(M = Mn, Fe, Co and Ni;x= 0.05) at 4.2 K in pulsed magnetic fields up to 31 T, we have found that the residual resistivity depends on the kind of guest species. Taking into account these results and available information, we have proposed a possible band model to understand the scattering mechanism by ionized impurities of the intercalated guest M2+and host Ti3+ions, in satisfactory agreement with the experiments.

ISSN:1058-725X    

DOI:10.1080/10587250008026117

出版商:Taylor & Francis Group    

年代:2000

数据来源: Taylor