Magnetism in Pd: Magnetoconductance and transport spectroscopy of atomic contacts
Magnetism in Pd: Magnetoconductance and transport spectroscopy of atomic contacts
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DOI：
10.1103/physrevb.94.144431
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发表时间：
2016-10
影响因子：
3.7
通讯作者：
F. Strigl;M. Keller;D. Weber;T. Pietsch;E. Scheer
中科院分区：
文献类型：
--
作者：
F. Strigl;M. Keller;D. Weber;T. Pietsch;E. Scheer
由于快速的技术进步对存储单元的要求越来越小，到目前为止，纳米材料中稳定的磁性秩序的出现引起了巨大的科学关注。电子输运光谱已被证明是研究原子接触的电子、磁和机械性质的一种通用工具。本文报道了低温下Pd原子接触的磁导和电学性质的综合实验研究。对电子输运谱和磁导曲线的分析表明，Pd单原子接触具有不同的行为，这归因于不同的接触构型。磁导表现出一种非单调但大部分是连续的行为，与带状铁磁体的原子接触中发现的行为相当。在dI/dV谱中，经常观察到明显的零偏压反常(ZBA)以及非周期和非对称的涨落模式。虽然ZBA可以被解释为近藤效应的迹象，暗示着磁性杂质的存在，但涨落是在电导涨落的框架下评估的，电导涨落与磁导轨迹和以前在Au原子接触中的发现有关。分析表明，Au原子接触的磁导和输运谱完全可以用电导起伏来解释，而在Pd接触中，需要存在局域磁序。
Since the rapid technological progress demands for ever smaller storage units, the emergence of stable magnetic order in nanomaterials down to the single-atom regime has attracted huge scientific attention to date. Electronic transport spectroscopy has been proven to be a versatile tool for the investigation of electronic, magnetic, and mechanical properties of atomic contacts. Here we report a comprehensive experimental study of the magnetoconductance and electronic properties of Pd atomic contacts at low temperature. The analysis of electronic transport $(dI/dV)$ spectra and the magnetoconductance curves yields a diverse behavior of Pd single-atom contacts, which is attributed to different contact configurations. The magnetoconductance shows a nonmonotonous but mostly continuous behavior, comparable to those found in atomic contacts of band ferromagnets. In the $dI/dV$ spectra, frequently, a pronounced zero-bias anomaly (ZBA) as well as an aperiodic and nonsymmetric fluctuation pattern are observed. While the ZBA can be interpreted as a sign of the Kondo effect, suggesting the presence of magnetic impurity, the fluctuations are evaluated in the framework of conductance fluctuations in relation to the magnetoconductance traces and to previous findings in Au atomic contacts. This thorough analysis reveals that the magnetoconductance and transport spectrum of Au atomic contacts can completely be accounted for by conductance fluctuations, while in Pd contacts the presence of local magnetic order is required.