NMR Study of Antiferromagnetic Spinel CoCo2O4 in Paramagnetic and Ordered State
| Autor: | Kazuo Miyatani, Toshio Fukai, Yuji Furukawa, Shinji Wada |
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| Rok vydání: | 1996 |
| Předmět: | |
| Zdroj: | Journal of the Physical Society of Japan. 65:4067-4071 |
| ISSN: | 1347-4073 0031-9015 |
| DOI: | 10.1143/jpsj.65.4067 |
| Popis: | Nuclear magnetic resonance of 59 Co at both the tetrahedral A-site and octahedral B-site in an older generation spinel compound of antiferromagnetic CoCo 2 O 4 ( T N =34 K) was carried out between T =1.4 and 300 K to provide additional information on the importance of the local crystal field parameters and electron-electron correlations. From an analysis of the T -independent relaxation rate of 59 Co at the A-site in the paramagnetic state, the super-exchange interaction J between the Co 2+ ions at the A-site through intervening O 2- and Co 3+ ions is estimated to be 0.050 cm -1 with an exchange frequency ω e =5.9×10 10 sec -1 , which can not simply be explained within the framework of the Weiss field. A small experimental value of the spin hyperfine field at the A-site, A s =1.63×10 -4 cm -1 , is well understood when the second-order orbital moment due to the spin-orbit interaction is taken into consideration. The energy difference Δ between t 2 g and e g orbitals at the A- and B-site in CoCo 2 O 4 is fo... |
| Databáze: | OpenAIRE |
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