Magnetic structures of βI-Li2CoSiO4 and γ0-Li2MnSiO4: crystal structure type vs. magnetic topology
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Date
2014-08
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Elsevier
Abstract
The magnetic structure and properties of the candidate lithium-ion battery cathode materials Pbn21(≡Pna21) Li2CoSiO4 and P21/n Li2MnSiO4 have been studied experimentally using low-temperature neutron powder diffraction and magnetometry. Both materials undergo long-range antiferromagnetic ordering, at 14 K and 12 K respectively, due to super–super-exchange mediated by bridging silicate groups. Despite having different crystal structures (wurtzite- vs. “dipolar”-type), Li2CoSiO4 and Li2MnSiO4 have the same topology in terms of magnetic interactions, and adopt collinear magnetic structures of the same type with the propagation vectors (0, 1/2, 1/2) and (1/2, 0, 1/2), respectively. The magnetic moments in the two materials are aligned in parallel and obliquely to the distorted closed-packed layers of oxygen atoms. The experimentally observed values of the ordered magnetic moments, 2.9 μB and 4.6 μB, are close to those expected for d7 Co2+ and d5 Mn2+, respectively.© 2014, Elsevier Inc.
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Keywords
Magnetism, Lithium ions, Cathodes, Neutrons, Antiferromagnetic materials, Silicates
Citation
Avdeev, M., Mohamed, Z., & Ling, C. D. (2014). Magnetic structures of βI-Li2CoSiO4 and γ0-Li2MnSiO4: crystal structure type vs. magnetic topology. Journal of Solid State Chemistry, 216(0), 42-48. doi:10.1016/j.jssc.2014.04.028