Magnetic domain structures are active electron transport agents and can be used to induce large magnetoresistance (MR), particularly in half-metallic solids. We have studied the excess resistance induced by a single magnetic domain wall in a one-dimensional half-metallic CrO₂ nanoscale conductor with a built-in constriction whose channel width (d) ranges from 30 to 200 nm. We observed that the domain wall-induced MR is enhanced by 70 fold when d decreases from 200 nm to 30 nm. We speculate that the enhancement is due to the increased domain wall resistance (DWR) and the extra contribution of ballistic magnetoresistance (BMR). We have uncovered a large size effect of d on the MR induced by the domain wall, which scales with d as d^{−1.87±0.32}. Accordingly, we predict that the MR ratio of a simple CrO₂ nanowire impregnated with a constriction at a 150 nm² cross-section could reach 100%. This large MR far exceeds that of a conventional ferromagnetic nanowire, confirming the role of half metallicity on enhanced magneto-transport.

中文翻译：

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半金属 CrO2 外延纳米结构中单畴壁的电阻

磁畴结构是活性电子传输剂，可用于诱导大磁阻 (MR)，尤其是在半金属固体中。我们研究了在一维半金属 CrO ₂纳米级导体中由单个磁畴壁引起的过电阻，该导体具有通道宽度 ( d ) 范围从 30 到 200 nm的内置收缩。我们观察到当d从 200 nm 减小到 30 nm时，畴壁诱导的 MR 增强了 70 倍。我们推测增强是由于畴壁电阻 (DWR) 的增加和弹道磁阻 (BMR) 的额外贡献。我们发现了d对畴壁引起的 MR的大尺寸效应，其与d为d ^-1.87±0.32。因此，我们预测在 150 nm ²截面处浸渍有收缩的简单 CrO ₂纳米线的 MR 比率可以达到 100%。这种大的 MR 远远超过了传统的铁磁纳米线，证实了半金属丰度对增强磁传输的作用。