Luo Ye-Cheng, Lin Dajun, Zhang Yan-Yan, Dong Song-Tao, Yao Shu-Hua, Lv Yang-Yang, Zhou Jian, Chen Y B
National Laboratory of Solid State Microstructures, Department of Physics, Nanjing University Nanjing 210093 China
National Laboratory of Solid State Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, Department of Materials Science and Engineering, Nanjing University Nanjing 210093 China.
RSC Adv. 2020 May 18;10(32):18753-18759. doi: 10.1039/d0ra02763d. eCollection 2020 May 14.
In this paper, we report on the transport and magnetic properties of layered oxytelluride BiCuTeO polycrystals with slight mixed valence of Cu. The temperature-dependent electrical resistivity reveals degenerate semiconductor behavior (similar to metals). Under the action of an external magnetic field, the BiCuTeO polycrystal sample exhibits unsaturated magnetic resistance (MR) of about 8% at 2 K and 9 Tesla. The Hall resistivities show nonlinear behavior, suggesting the coexistence of both electrons and holes in the sample. When the temperature is decreased to around 110 K, the dominant carriers are changed from electrons to holes from the viewpoint of electrical transport, which is supported by the calculated temperature-dependent Fermi energy. Meanwhile, at low temperatures (<100 K), the impurity magnetic moment formed by a small amount of positive divalent copper exhibits short-range magnetism (a spin-glass-like feature), which gives rise to a narrow magnetic hysteresis loop. Our work may benefit in-depth understanding of physical properties of BiCuTeO-based materials.
在本文中，我们报道了具有轻微铜混合价态的层状氧碲化物BiCuTeO多晶体的输运和磁性特性。随温度变化的电阻率揭示了简并半导体行为（类似于金属）。在外部磁场作用下，BiCuTeO多晶体样品在2 K和9特斯拉时表现出约8%的不饱和磁电阻（MR）。霍尔电阻率呈现非线性行为，表明样品中电子和空穴共存。从电输运的角度来看，当温度降至约110 K时，主导载流子从电子变为空穴，这一点得到了计算出的随温度变化的费米能的支持。同时，在低温（<100 K）下，由少量正二价铜形成的杂质磁矩表现出短程磁性（类似自旋玻璃的特征），这导致了一个狭窄的磁滞回线。我们的工作可能有助于深入理解基于BiCuTeO的材料的物理性质。
