Wang Longsheng, Tian Jianjun, Kang Chaoyang, Gu Haiyang, Pang Rui, Shen Mengna, She Limin, Song Yeheng, Liu Xiansheng, Zhang Weifeng
Research Center of Topological Functional Materials and Henan Key Laboratory of Photovoltaic Materials, Henan University, Kaifeng475004, China.
Inorg Chem. 2022 Nov 28;61(47):18899-18906. doi: 10.1021/acs.inorgchem.2c02801. Epub 2022 Nov 11.
The extreme magnetoresistance (XMR) of some compounds, challenging our understanding of magnetoresistance, is an interesting topic in condensed-matter and materials physics and future device applications. Here, we reported magnetotransport and magnetic properties of the as-grown and post-annealed TaCoTe single crystals. The resistivity evolution with temperature in the two TaCoTe single crystals shows a metallic behavior. Below 50 K, the XMR effect for the two crystals is found, and MR values at 3 K under 9 T are about 3.72 × 10% for the as-grown TaCoTe and 5.71 × 10% for the annealed samples, larger than that of the previous report. The studies on the Hall effect of the two TaCoTe single crystals indicate the multiband feature with high carrier mobilities from a two-band model. Electron and hole concentrations and mobilities of as-grown samples are comparable, while for the annealed sample, the hole concentration and mobility are larger than the electron concentration and mobility. The carrier mobilities for the two TaCoTe single crystals have the same order of magnitude, ∼10 cm V s. The XMR effect may be from high carrier mobilities. Magnetization of the as-grown TaCoTe decreases with increasing temperature, and a weaker magnetic transition at ∼150 K is observed. The annealed TaCoTe shows no magnetic transition and just a paramagnetic behavior with rising temperature. These results indicate that defects/deficiencies may play an important role in magnetotransport and magnetic properties of the two TaCoTe single crystals. These results are helpful in deeply understanding the XMR mechanism and magnetic properties in TaCoTe and offer a way to study the magnetic properties of the XMR Co-Te system.
一些化合物的极端磁电阻（XMR）挑战着我们对磁电阻的理解，是凝聚态和材料物理以及未来器件应用中的一个有趣话题。在此，我们报道了生长态和退火后的TaCoTe单晶的磁输运和磁性。两个TaCoTe单晶的电阻率随温度的变化呈现出金属行为。在50 K以下，发现了这两个晶体的XMR效应，在9 T磁场下3 K时，生长态TaCoTe的磁电阻值约为3.72×10%，退火样品的磁电阻值约为5.71×10%，比之前的报道值更大。对两个TaCoTe单晶的霍尔效应研究表明，从双带模型来看具有高载流子迁移率的多带特征。生长态样品的电子和空穴浓度及迁移率相当，而对于退火样品，空穴浓度和迁移率大于电子浓度和迁移率。两个TaCoTe单晶的载流子迁移率具有相同的数量级，约为10 cm² V⁻¹ s⁻¹。XMR效应可能源于高载流子迁移率。生长态TaCoTe的磁化强度随温度升高而降低，在约150 K处观察到较弱的磁转变。退火后的TaCoTe没有磁转变，仅表现出随温度升高的顺磁行为。这些结果表明，缺陷/不足可能在两个TaCoTe单晶的磁输运和磁性中起重要作用。这些结果有助于深入理解TaCoTe中的XMR机制和磁性，并为研究XMR Co-Te体系的磁性提供了一种方法。
