Stabilization of the spin density wave structure with rare-earth substitution in Ca3Co2O6

Jain, Anil ; Yusuf, S. M. ; Meena, S. S. ; Ritter, Clemens (2013) Stabilization of the spin density wave structure with rare-earth substitution in Ca3Co2O6 Physical Review B, 87 (9). Article ID 094411. ISSN 0163-1829

Full text not available from this repository.

Official URL:

Related URL:


We report the structural and magnetic properties of rare-earth substituted spin-chain compounds Ca2.75R0.25Co2O6 (R = Dy and Lu). The Rietveld refinement of neutron and x-ray powder diffraction patterns confirms the single-phase formation of both compounds in the rhombohedral structure (space group R3c). The derived values (from the analysis of the neutron diffraction patterns at 50 K) of the bond-valence sum indicate a reduction in the oxidation state of the cobalt ions at the trigonal prism (TP) site (6a) with R substitution, which is further supported by low temperature neutron diffraction [where a zero value of the ordered moment at the 6b site and a reduction in the values of the maximum ordered moment at the TP site have been observed] and dc magnetization studies. In the neutron diffraction patterns, additional Bragg peaks appear for both compounds below Néel temperature (TN) of ∼16 K, indicating the onset of an antiferromagnetic ordering of cobalt spin chains on the triangular lattice. The magnetic structure corresponds to a spin density wave (SDW) structure [with a propagation vector k={0,0,1.02}], having c axis as a direction of both moment and modulation. For both compounds, the refined values of the ordered moment at the 18e, 6b, and 6a sites are ∼0.03(2),0.02(2), and 4.2 (2) μB, respectively. Unlike the parent compound Ca3Co2O6, no temperature dependence as well as no time dependence in the intensity of the strongest antiferromagnetic reflection (10 τ), corresponding to the propagation vector k = {0, 0, 1.02}, has been observed down to 1.5 K confirming that the SDW structure is stabilized by the substitution with rare-earth ions. The stabilization of the SDW structure and the observed decrease in the values of TN could be due to a decrease in the value of positive FM intrachain exchange interaction J with the rare-earth substitution in a system with competing intrachain and interchain exchange interactions.

Item Type:Article
Source:Copyright of this article belongs to American Physical Society.
ID Code:112081
Deposited On:01 Dec 2017 12:10
Last Modified:01 Dec 2017 12:10

Repository Staff Only: item control page