|
| | | | |
| | | |
| Stat |
Members: 3645
Articles: 2'506'133
Articles rated: 2609
26 April 2024 |
|
| | | | |
|
Article overview
| |
|
|
On the Origin of the Metallic and Anisotropic Magnetic Properties of Na_xCoO_2 (x~~0.75) | | M.-H. Whangbo
; D. Dai
; R. K. Kremer
; | | Date: |
5 Jun 2006 | | Subject: | Strongly Correlated Electrons; Materials Science | | Abstract: | Non-stoichiometric NaxCoO2 (0.5 < x < 1) consists of CoO2 layers made up of edge-sharing CoO6 octahedra, and exhibits strongly anisotropic magnetic susceptibilities as well as metallic properties. A modified Curie-Weiss law was proposed for systems containing anisotropic magnetic ions to analyze the magnetic susceptibilities of NaxCoO2 (x ~~ 0.75), and implications of this analysis were explored. Our study shows that the lowspin Co4+ (S = 1/2) ions of NaxCoO2 generated by the Na vacancies cause the anisotropic magnetic properties of NaxCoO2, and suggests that the six nearest-neighbor Co3+ ions of each Co4+ ion adopt the intermediate-spin electron configuration thereby behaving magnetically like low-spin Co4+ ions. The Weiss temperature of NaxCoO2 is more negative along the direction of the lower g-factor (i.e., Theta_parallel < Theta_perp < 0, and g_parallel < g_perp). The occurrence of intermediate-spin Co3+ ions surrounding each Co4+ ion account for the apparently puzzling magnetic properties of NaxCoO2 (x ~~ 0.75), i.e., the large negative Weiss temperature, the three-dimensional antiferromagnetic ordering below ~22 K, and the metallic properties. The picture of the magnetic structure derived from neutron scattering studies below ~22 K are in apparent conflict with that deduced from magnetic susceptibility measurements between ~50 - 300 K. These conflicting pictures are resolved by noting that the spin exchange between Co3+ ions is more strongly antiferromagnetic than that between Co4+ and Co3+ ions. | | Source: | arXiv, cond-mat/0606103 | | Services: | Forum | Review | PDF | Favorites | |
|
|
No review found.
Did you like this article?
Note: answers to reviews or questions about the article must be posted in the forum section.
Authors are not allowed to review their own article. They can use the forum section.
|
| |
|
|
|
|
News, job offers and information for researchers and scientists:
| |
REGISTER