2024-03-29T00:40:07Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/398442022-11-17T02:08:08Zhdl_2115_20045hdl_2115_139Electronic phase diagram of the layered cobalt oxide system LixCoO2 (0.0 ≤ x ≤ 1.0)Motohashi, T.Ono, T.Sugimoto, Y.Masubuchi, Y.Kikkawa, S.Kanno, R.Karppinen, M.Yamauchi, H.antiferromagnetic materialscharge-ordered stateselectron correlationslithium compoundsmagnetic susceptibilitymagnetic transitionsnuclear quadrupole resonanceparamagnetism427Here we report the magnetic properties of the layered cobalt oxide system, LixCoO2, in the whole range of Li composition, 0 ≤ x ≤ 1. Based on dc-magnetic-susceptibility data, combined with results of Co-59 nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) observations, the electronic phase diagram of LixCoO2 has been established. As in the related material NaxCoO2, a magnetic critical point is found to exist between x=0.35 and 0.40, which separates the Pauli-paramagnetic and Curie-Weiss metals. In the Pauli-paramagnetic regime (x ≤ 0.35), the antiferromagnetic spin correlations systematically increase with decreasing x. Nevertheless, CoO2, the x=0 end member is a noncorrelated metal in the whole temperature range studied. In the Curie-Weiss regime (x ≥ 0.40), on the other hand, various phase transitions are observed. For x=0.40, a susceptibility hump is seen at 30 K, suggesting the onset of static antiferromagnetic order. A magnetic jump, which is likely to be triggered by charge ordering, is clearly observed at T-t ≈ 175 K in samples with x=0.50 (=1/2) and 0.67 (=2/3), while only a tiny kink appears at T ≈ 210 K in the sample with an intermediate Li composition, x=0.60. Thus, the phase diagram of the LixCoO2 system is complex and the electronic properties are sensitively influenced by the Li content (x).American Physical SocietyJournal Articleapplication/pdfhttp://hdl.handle.net/2115/39844https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/39844/1/PRB80-16_165114.pdf1098-0121Physical Review B80161651142009-10enginfo:doi/10.1103/PhysRevB.80.165114© 2009 The American Physical Societypublisher