Tuning the Magnetic Properties of LixCrTi0.25Se2 (0.03≤x≤0.7) by Directed Deintercalation of Lithium

Malte Behrens, Joseph Wontcheu, Wolff-Ragnar Kiebach, Wolfgang Bensch

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

X-ray diffraction (XRD), in situ energy-dispersive X-ray diffraction (EDXRD), X-ray absorption near-edge structure (XANES), extended X-ray absorption fine structure (EXAFS), and magnetic measurements were applied to investigate the effects of lithium deintercalation on pseudolayered Li0.70CrTi0.25Se2. A detailed picture of structural changes during the deintercalation process was obtained by combining the results of EDXRD and EXAFS. Removal of Li from the host–guest complex leads to anisotropic contraction of the unit cell with stronger impact on the c axis, which is the stacking axis of the layers. The EDXRD experiments evidence that the shrinkage of the lattice parameters with decreasing xLi in LixCrTi0.25Se2 is nonlinear in the beginning and then becomes linear. Analysis of the EXAFS spectra clearly shows that the Cr/Ti—Se distances are affected in a different manner by Li removal. The Cr—Se bond lengths decrease, whereas the Ti—Se bonds lengthen when the Li content is reduced, which is consistent with XRD data. Magnetic measurements reveal a change from predominantly antiferromagnetic exchange (θp=−300 K) interactions for the pristine material to ferromagnetic exchange interactions (θ=25 K) for the fully intercalated material. Thus, the magnetic properties can be altered under ambient conditions by directed adjustment of the dominant magnetic exchange. The unusual magnetic behavior can be explained on the basis of the variation of the metal–metal distances and the Cr-Se-Cr angles with x, which were determined by Rietveld refinements. Owing to competing ferromagnetic and antiferromagnetic exchange interactions and disorder, the magnetic ground state of the intercalated materials is characterized by spin-glass or spin-glass-like behavior.
Original languageEnglish
JournalChemistry - A European journal
Volume14
Issue number16
Pages (from-to)5021-5029
ISSN0947-6539
DOIs
Publication statusPublished - 2008
Externally publishedYes

Cite this

@article{d8d65e4709ff463fab09abe353a6838c,
title = "Tuning the Magnetic Properties of LixCrTi0.25Se2 (0.03≤x≤0.7) by Directed Deintercalation of Lithium",
abstract = "X-ray diffraction (XRD), in situ energy-dispersive X-ray diffraction (EDXRD), X-ray absorption near-edge structure (XANES), extended X-ray absorption fine structure (EXAFS), and magnetic measurements were applied to investigate the effects of lithium deintercalation on pseudolayered Li0.70CrTi0.25Se2. A detailed picture of structural changes during the deintercalation process was obtained by combining the results of EDXRD and EXAFS. Removal of Li from the host–guest complex leads to anisotropic contraction of the unit cell with stronger impact on the c axis, which is the stacking axis of the layers. The EDXRD experiments evidence that the shrinkage of the lattice parameters with decreasing xLi in LixCrTi0.25Se2 is nonlinear in the beginning and then becomes linear. Analysis of the EXAFS spectra clearly shows that the Cr/Ti—Se distances are affected in a different manner by Li removal. The Cr—Se bond lengths decrease, whereas the Ti—Se bonds lengthen when the Li content is reduced, which is consistent with XRD data. Magnetic measurements reveal a change from predominantly antiferromagnetic exchange (θp=−300 K) interactions for the pristine material to ferromagnetic exchange interactions (θ=25 K) for the fully intercalated material. Thus, the magnetic properties can be altered under ambient conditions by directed adjustment of the dominant magnetic exchange. The unusual magnetic behavior can be explained on the basis of the variation of the metal–metal distances and the Cr-Se-Cr angles with x, which were determined by Rietveld refinements. Owing to competing ferromagnetic and antiferromagnetic exchange interactions and disorder, the magnetic ground state of the intercalated materials is characterized by spin-glass or spin-glass-like behavior.",
author = "Malte Behrens and Joseph Wontcheu and Wolff-Ragnar Kiebach and Wolfgang Bensch",
year = "2008",
doi = "10.1002/chem.200701471",
language = "English",
volume = "14",
pages = "5021--5029",
journal = "Chemistry: A European Journal",
issn = "0947-6539",
publisher = "Wiley - V C H Verlag GmbH & Co. KGaA",
number = "16",

}

Tuning the Magnetic Properties of LixCrTi0.25Se2 (0.03≤x≤0.7) by Directed Deintercalation of Lithium. / Behrens, Malte; Wontcheu, Joseph; Kiebach, Wolff-Ragnar; Bensch, Wolfgang.

In: Chemistry - A European journal, Vol. 14, No. 16, 2008, p. 5021-5029.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Tuning the Magnetic Properties of LixCrTi0.25Se2 (0.03≤x≤0.7) by Directed Deintercalation of Lithium

AU - Behrens, Malte

AU - Wontcheu, Joseph

AU - Kiebach, Wolff-Ragnar

AU - Bensch, Wolfgang

PY - 2008

Y1 - 2008

N2 - X-ray diffraction (XRD), in situ energy-dispersive X-ray diffraction (EDXRD), X-ray absorption near-edge structure (XANES), extended X-ray absorption fine structure (EXAFS), and magnetic measurements were applied to investigate the effects of lithium deintercalation on pseudolayered Li0.70CrTi0.25Se2. A detailed picture of structural changes during the deintercalation process was obtained by combining the results of EDXRD and EXAFS. Removal of Li from the host–guest complex leads to anisotropic contraction of the unit cell with stronger impact on the c axis, which is the stacking axis of the layers. The EDXRD experiments evidence that the shrinkage of the lattice parameters with decreasing xLi in LixCrTi0.25Se2 is nonlinear in the beginning and then becomes linear. Analysis of the EXAFS spectra clearly shows that the Cr/Ti—Se distances are affected in a different manner by Li removal. The Cr—Se bond lengths decrease, whereas the Ti—Se bonds lengthen when the Li content is reduced, which is consistent with XRD data. Magnetic measurements reveal a change from predominantly antiferromagnetic exchange (θp=−300 K) interactions for the pristine material to ferromagnetic exchange interactions (θ=25 K) for the fully intercalated material. Thus, the magnetic properties can be altered under ambient conditions by directed adjustment of the dominant magnetic exchange. The unusual magnetic behavior can be explained on the basis of the variation of the metal–metal distances and the Cr-Se-Cr angles with x, which were determined by Rietveld refinements. Owing to competing ferromagnetic and antiferromagnetic exchange interactions and disorder, the magnetic ground state of the intercalated materials is characterized by spin-glass or spin-glass-like behavior.

AB - X-ray diffraction (XRD), in situ energy-dispersive X-ray diffraction (EDXRD), X-ray absorption near-edge structure (XANES), extended X-ray absorption fine structure (EXAFS), and magnetic measurements were applied to investigate the effects of lithium deintercalation on pseudolayered Li0.70CrTi0.25Se2. A detailed picture of structural changes during the deintercalation process was obtained by combining the results of EDXRD and EXAFS. Removal of Li from the host–guest complex leads to anisotropic contraction of the unit cell with stronger impact on the c axis, which is the stacking axis of the layers. The EDXRD experiments evidence that the shrinkage of the lattice parameters with decreasing xLi in LixCrTi0.25Se2 is nonlinear in the beginning and then becomes linear. Analysis of the EXAFS spectra clearly shows that the Cr/Ti—Se distances are affected in a different manner by Li removal. The Cr—Se bond lengths decrease, whereas the Ti—Se bonds lengthen when the Li content is reduced, which is consistent with XRD data. Magnetic measurements reveal a change from predominantly antiferromagnetic exchange (θp=−300 K) interactions for the pristine material to ferromagnetic exchange interactions (θ=25 K) for the fully intercalated material. Thus, the magnetic properties can be altered under ambient conditions by directed adjustment of the dominant magnetic exchange. The unusual magnetic behavior can be explained on the basis of the variation of the metal–metal distances and the Cr-Se-Cr angles with x, which were determined by Rietveld refinements. Owing to competing ferromagnetic and antiferromagnetic exchange interactions and disorder, the magnetic ground state of the intercalated materials is characterized by spin-glass or spin-glass-like behavior.

U2 - 10.1002/chem.200701471

DO - 10.1002/chem.200701471

M3 - Journal article

VL - 14

SP - 5021

EP - 5029

JO - Chemistry: A European Journal

JF - Chemistry: A European Journal

SN - 0947-6539

IS - 16

ER -