Magnetic Correlation of NaxCoO2 and Successive Phase Transitions of Na0:5CoO2 —NMR and Neutron Diffraction Studies—
Magnetic Correlation of NaxCoO2 and Successive Phase Transitions of Na0:5CoO2 —NMR and Neutron Diffraction Studies—
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DOI：
10.1143/jpsj.74.3046
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发表时间：
2005-06
影响因子：
1.7
通讯作者：
M. Yokoi;T. Moyoshi;Y. Kobayashi;M. Soda;Y. Yasui;M. Sato;K. Kakurai
中科院分区：
文献类型：
--
作者：
M. Yokoi;T. Moyoshi;Y. Kobayashi;M. Soda;Y. Yasui;M. Sato;K. Kakurai
给出了Na x CoO 2 、特别是Na 0.5 CoO 2 的通过包括NMR/NQR和中子散射的各种方法获得的数据。该系统的电子性质对 x 的依赖性也受到了关注。强调了在 x < x c ∼0.6 区域观察到的类伪带隙行为。对于x≤0.6的样品，观察到来自两种不同四极频率ν Q 分别为∼4.1和∼2.8 MHz的Co位点的信号，并且随着x减小到0.3，前者ν Q 几乎等于超导系统Na 0.3 CoO 2 · y H 2 O的信号。对于Na 0.5 CoO 2 ，ν Q 越大的Co位点具有越大的磁矩。它们在 T c1 ∼87 K 处与平面内的方向反铁磁排列，而具有较小 ν Q 的 Co 位具有较小的力矩。它们沿平行于 c 轴的方向排列。两个不同位点的有序矩表现出相同的 T 依赖性，表明这些位点的存在不是由于宏观......
Data taken by various methods including NMR/NQR and neutron scattering are presented for Na x CoO 2 , particularly Na 0.5 CoO 2 . Attention has also been paid to the x dependence of the electronic nature of this system. The pseudo-gap-like behavior observed in the region of x < x c ∼0.6 is emphasized. For samples with x ≤0.6, signals from two kinds of Co sites with different quadrupole frequencies ν Q of ∼4.1 and ∼2.8 MHz were observed, and the former ν Q , which is nearly equal to that of the superconducting system Na 0.3 CoO 2 · y H 2 O, becomes dominant with decreasing x to 0.3. For Na 0.5 CoO 2 , the Co sites with the larger ν Q have larger magnetic moments. They align antiferromagnetically at T c1 ∼87 K with their direction within the plane, while the Co sites with the smaller ν Q have smaller moments. They align in the direction parallel to the c axis. The ordered moments at the two distinct sites exhibit the same T -dependence, indicating that the existence of these sites is not due to macroscopic ...