Unexpected magnetic properties of gas-stabilized platinum nanostructures in the tunneling regime.
Unexpected magnetic properties of gas-stabilized platinum nanostructures in the tunneling regime.
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DOI：
10.1021/nl504254d
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发表时间：
2015-01
期刊：
影响因子：
10.8
通讯作者：
O. Cespedes;M. Wheeler;T. Moorsom;M. Viret
中科院分区：
文献类型：
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作者：
O. Cespedes;M. Wheeler;T. Moorsom;M. Viret
纳米结构材料通常具有与本体材料大不相同的性质，这是由材料的物理性质的量子限制所强加的。这包括，例如，超顺磁性和量子化电导，但原始的性质，如磁阻的分子结构也可能出现。在这封信中，我们报告的原子操纵铂纳米接触，以诱导磁电阻。铂是一种顺磁性5d金属，但据预测，这种材料的原子链是磁有序的，具有很大的各向异性。值得注意的是，我们发现，气流稳定Pt原子结构在一个中断结实验，我们观察到非凡的电阻变化超过30,000%的温度范围内高达77 K。模拟表明，这种行为可能源于以前未知的磁有序，低能量状态的氧化铂原子链。这是支持在Pt/PtOx超晶格的测量揭示了铁磁矩的存在。这些特性为原子尺度的“脏”磁传感器和量子器件的研究开辟了新的道路。
Nanostructured materials often have properties widely different from bulk, imposed by quantum limits to a physical property of the material. This includes, for example, superparamagnetism and quantized conductance, but original properties such as magnetoresistance in nonmagnetic molecular structures may also emerge. In this Letter, we report on the atomic manipulation of platinum nanocontacts in order to induce magnetoresistance. Platinum is a paramagnetic 5d metal, but atomic chains of this material have been predicted to be magnetically ordered with a large anisotropy. Remarkably, we find that a gas flow stabilizes Pt atomic structures in a break junction experiment, where we observe extraordinary resistance changes over 30,000% in a temperature range up to 77 K. Simulations indicate that this behavior may stem from a previously unknown magnetically ordered, low-energy state in platinum oxide atomic chains. This is supported by measurements in Pt/PtOx superlattices revealing the presence of a ferromagnetic moment. These properties open new paths of research for atomic scale "dirty" magnetic sensors and quantum devices.