Magnetoresistance and magnetothermopower in the rhodium misfit oxide [Bi1.95Ba1.95Rh0.1O4][RhO2]1.8
Magnetoresistance and magnetothermopower in the rhodium misfit oxide [Bi1.95Ba1.95Rh0.1O4][RhO2]1.8
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DOI：
10.1103/physrevb.73.165121
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发表时间：
2006-04-01
影响因子：
3.7
通讯作者：
Maignan, A
中科院分区：
文献类型：
--
作者：
Klein, Y;Hébert, S;Maignan, A
研究了Rh基[Bi1.95Ba1.95Rh0.1O4][RhO2](1.8)错配氧化物的磁输运性质。观察到金属行为，在室温下与 +95 mu V/K 的大热电势 S 共存，类似于在钴基错配氧化物中观察到的情况。该S值可以通过RhO2层中Rh3+(4d(6))和Rh4+(4d(5))的共存来解释，这表明它们与钴错配氧化物中的等电子低自旋态t(2g)(6) S=0 Co3+ (3d(6))和t(2g)(5) S=1/2 Co4+ (3d(5))具有相同的影响。从比热测量结果来看，系数gamma=38 mJ K-2 mol(Rh)(-1)表明电子相关性中等强。在低 T 下观察到小的磁阻，有两个贡献，第一个为负值，最高为 7 T，第二个为 mu H-0 > 7 T，为正值，在 14 T 和 T=2.5 K 时达到 +5%。这是氧化铑中磁阻的独特示例，强调了这些 CdI2 型层产生的传输特性的特殊性。热电势也强烈依赖于磁场，在 9 T、2.5 K 时磁热电势达到 -50%。
The magnetotransport properties of the Rh-based [Bi1.95Ba1.95Rh0.1O4][RhO2](1.8) misfit oxide have been investigated. A metallic behavior is observed, coexisting with a large thermopower S of +95 mu V/K at room temperature, similar to what is observed in cobalt based misfit oxides. This S value can be explained by the coexistence of Rh3+(4d(6)) and Rh4+(4d(5)) in the RhO2 layers, suggesting that they have the same influence as isoelectronic low spin state t(2g)(6) S=0 Co3+ (3d(6)) and t(2g)(5) S=1/2 Co4+ (3d(5)) in cobalt misfit oxides. From the specific heat measurements, the coefficient gamma=38 mJ K-2 mol(Rh)(-1) shows that electron correlations are moderately strong. A small magnetoresistance is observed at low T, with two contributions, first negative up to 7 T, and positive for mu H-0 > 7 T, reaching +5% at 14 T and T=2.5 K. This is a unique example of magnetoresistance in rhodium oxides, emphasizing the peculiarity of the transport properties arising from these CdI2 type layers. The thermopower depends also strongly on field, with a magnetothermopower reaching -50% in 9 T at 2.5 K.