Details
| Originalsprache | Englisch |
|---|---|
| Seiten (von - bis) | 288-299 |
| Seitenumfang | 12 |
| Fachzeitschrift | Journal of the American Chemical Society |
| Jahrgang | 130 |
| Ausgabenummer | 1 |
| Publikationsstatus | Veröffentlicht - 9 Jan. 2008 |
Abstract
The room temperature intercalation of Cr2Ti3Se 8 with butyl lithium yields a phase mixture of the starting material and of the new trigonal phase with composition Li0.4Cr 0.5Ti0.75Se2. The phase pure fully intercalated trigonal phase is obtained at elevated temperature (80°C) with the final composition Li0.62Cr0.5Ti0.75Se2. The line profile analysis (LPA) of the powder patterns shows that pronounced strain occurs in the intercalated material. The deintercalation of the material is realized by treatment of the fully intercalated sample with distilled water leading to the composition Li0.15Cr0.5Ti 0.75Se2. The intercalation is accompanied by an electron transfer from the guest Li to the host material, and as a consequence significant changes of the interatomic distances are observed. The local environment and the dynamics of the Li+ ions in the fully intercalated sample were studied with 7Li magic angle spinning (MAS) NMR investigations. These reveal different environments of transition metal neighbors for the Li sites and a high mobility of the Li ions. Magnetic measurements show that in the pristine material antiferromagnetic interactions are dominating (θ = -113.5 K) with no long-range order at low temperatures. The magnetic ground state is characterized by a spin-glass behavior. With increasing Li content the antiferromagnetic character vanishes progressively, and the fully intercalated phase exhibits a positive Weiss constant (θ = 12 K) indicating dominating ferromagnetic exchange interactions; i.e., the magnetic properties can be significantly altered by lithiation. The interpretation of our experimental findings is supported by the results of accompanying band structure calculations done within the framework of local spin density functional theory. These demonstrate in particular the role of the charge transfer between the constituents as a function of the Li concentration and its impact on the exchange coupling.
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- Katalyse
- Chemie (insg.)
- Allgemeine Chemie
- Biochemie, Genetik und Molekularbiologie (insg.)
- Biochemie
- Chemische Verfahrenstechnik (insg.)
- Kolloid- und Oberflächenchemie
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in: Journal of the American Chemical Society, Jahrgang 130, Nr. 1, 09.01.2008, S. 288-299.
Publikation: Beitrag in Fachzeitschrift › Artikel › Forschung › Peer-Review
}
TY - JOUR
T1 - Tuning the structural and physical properties of Cr2Ti 3Se8 by lithium intercalation
T2 - A study of the magnetic properties, investigation of ion mobility with NMR spectroscopy and electronic band structure calculations
AU - Wontcheu, Joseph
AU - Bensch, Wolfgang
AU - Wilkening, Martin
AU - Heitjans, Paul
AU - Indris, Sylvio
AU - Sideris, Paul
AU - Grey, Clare P.
AU - Mankovsky, Sergiy
AU - Ebert, Hubert
PY - 2008/1/9
Y1 - 2008/1/9
N2 - The room temperature intercalation of Cr2Ti3Se 8 with butyl lithium yields a phase mixture of the starting material and of the new trigonal phase with composition Li0.4Cr 0.5Ti0.75Se2. The phase pure fully intercalated trigonal phase is obtained at elevated temperature (80°C) with the final composition Li0.62Cr0.5Ti0.75Se2. The line profile analysis (LPA) of the powder patterns shows that pronounced strain occurs in the intercalated material. The deintercalation of the material is realized by treatment of the fully intercalated sample with distilled water leading to the composition Li0.15Cr0.5Ti 0.75Se2. The intercalation is accompanied by an electron transfer from the guest Li to the host material, and as a consequence significant changes of the interatomic distances are observed. The local environment and the dynamics of the Li+ ions in the fully intercalated sample were studied with 7Li magic angle spinning (MAS) NMR investigations. These reveal different environments of transition metal neighbors for the Li sites and a high mobility of the Li ions. Magnetic measurements show that in the pristine material antiferromagnetic interactions are dominating (θ = -113.5 K) with no long-range order at low temperatures. The magnetic ground state is characterized by a spin-glass behavior. With increasing Li content the antiferromagnetic character vanishes progressively, and the fully intercalated phase exhibits a positive Weiss constant (θ = 12 K) indicating dominating ferromagnetic exchange interactions; i.e., the magnetic properties can be significantly altered by lithiation. The interpretation of our experimental findings is supported by the results of accompanying band structure calculations done within the framework of local spin density functional theory. These demonstrate in particular the role of the charge transfer between the constituents as a function of the Li concentration and its impact on the exchange coupling.
AB - The room temperature intercalation of Cr2Ti3Se 8 with butyl lithium yields a phase mixture of the starting material and of the new trigonal phase with composition Li0.4Cr 0.5Ti0.75Se2. The phase pure fully intercalated trigonal phase is obtained at elevated temperature (80°C) with the final composition Li0.62Cr0.5Ti0.75Se2. The line profile analysis (LPA) of the powder patterns shows that pronounced strain occurs in the intercalated material. The deintercalation of the material is realized by treatment of the fully intercalated sample with distilled water leading to the composition Li0.15Cr0.5Ti 0.75Se2. The intercalation is accompanied by an electron transfer from the guest Li to the host material, and as a consequence significant changes of the interatomic distances are observed. The local environment and the dynamics of the Li+ ions in the fully intercalated sample were studied with 7Li magic angle spinning (MAS) NMR investigations. These reveal different environments of transition metal neighbors for the Li sites and a high mobility of the Li ions. Magnetic measurements show that in the pristine material antiferromagnetic interactions are dominating (θ = -113.5 K) with no long-range order at low temperatures. The magnetic ground state is characterized by a spin-glass behavior. With increasing Li content the antiferromagnetic character vanishes progressively, and the fully intercalated phase exhibits a positive Weiss constant (θ = 12 K) indicating dominating ferromagnetic exchange interactions; i.e., the magnetic properties can be significantly altered by lithiation. The interpretation of our experimental findings is supported by the results of accompanying band structure calculations done within the framework of local spin density functional theory. These demonstrate in particular the role of the charge transfer between the constituents as a function of the Li concentration and its impact on the exchange coupling.
UR - http://www.scopus.com/inward/record.url?scp=38349032886&partnerID=8YFLogxK
U2 - 10.1021/ja076082+
DO - 10.1021/ja076082+
M3 - Article
AN - SCOPUS:38349032886
VL - 130
SP - 288
EP - 299
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
SN - 0002-7863
IS - 1
ER -