已为您找到该学者10条结果 成果回收站
-
75浏览
-
0点赞
-
0收藏
-
0分享
-
197下载
-
0
-
引用
-
63浏览
-
0点赞
-
0收藏
-
0分享
-
189下载
-
0
-
引用
曹光旱, Guanghan
J. Phys. D: Appl. Phys. 40 (2007) 2899-2905,-0001,():
-1年11月30日
CaCu3Ti4O12
-
51浏览
-
0点赞
-
0收藏
-
0分享
-
381下载
-
0
-
引用
曹光旱, Guanghan
PHYSICAL REVIEW B 69, 045106 (2004),-0001,():
-1年11月30日
The pseudobinary thiospinel system Cu1-xCdxIr2S4 was investigated by the x-ray-diffraction, electrical resistivity, magnetic-susceptibility, and specific-heat measurements. It was shown that the system exhibits a miscibility-gap behavior for the Cd substitution, however, nearly monophasic samples were obtained by quenching at 1373 K, except for 0.4<x≤0.6. With increasing the Cd concentration, the room-temperature electrical conductivity and Pauli susceptibility decrease monotonically, consistent with the hole-filling picture. The first-order metal-insulator transition at about 230 K in the parent compound CuIr2S4 is changed into a second-order transition around 185 K when x~0.25, whereafter the second-order transition disappears at x~0.8. No superconductivity was observed down to 1.8 K. The end-member compound CdIr2S4 is shown as an insulator with a band gap of 0.3 eV. Analysis for the data of magnetic susceptibility and electrical resistivity suggests the formation of bipolarons below 185 K for 0.25<x<0.8, which accounts for the absence of superconductivity in terms of the transition from the BCS Cooper pairs to small bipolarons.
-
49浏览
-
0点赞
-
0收藏
-
0分享
-
164下载
-
0
-
引用
曹光旱, Zhi
J. Phys.: Condens. Matter 18 (2006) L379-L384,-0001,():
-1年11月30日
We report the measurements of thermopower, electrical resistivity and thermal conductivity in a complex cobalt oxide Li0.48Na0.35CoO2, whose crystal structure can be viewed as an intergrowth of the O3 phase of LixCoO2 and the P2 phase of NayCoO2 along the c-axis. The compound shows a large roomtemperature thermopower of ∼180 μV K−1, which is substantially higher than those of LixCoO2 and NayCoO2. The figure of merit for the polycrystalline sample increases rapidly with increasing temperature, and achieves nearly 10−4 K−1 at 300 K, suggesting that the LixNayCoO2 system is a promising candidate for thermoelectric applications.
-
44浏览
-
0点赞
-
0收藏
-
0分享
-
182下载
-
0
-
引用