CRANN, School of Physics, Trinity College Dublin, Dublin 2, Ireland.
Nano Lett. 2010 Apr 14;10(4):1132-6. doi: 10.1021/nl902973p.
We have probed one antiferromagnetic (AF) antiphase boundary (APB) and a single Fe(3)O(4) domain using nanogap contacts. Our experiments directly demonstrate that, in the case of probing one AF-APB, a large magnetoresistance (MR), high resistivity, and a high saturation field are observed as compared with the case of probing a single Fe(3)O(4) domain. The shape of the temperature-dependent MR curves is also found to differ between the single domain and one of the AF-APB measurements, with a characteristic strong temperature dependence for the single domain and temperature independence for the one AF-APB case. We argue that these observations are indicative of profound changes in the electronic transport across APBs. The investigated APB defects increase the activation energy and disturb the long-range charge ordering of monodomain Fe(3)O(4).
我们使用纳米间隙接触探测了一个反铁磁（AF）反相畴界（APB）和单个 Fe(3)O(4)畴。我们的实验直接证明，在探测一个 AF-APB 的情况下，与探测单个 Fe(3)O(4)畴的情况相比，观察到了大磁电阻（MR）、高电阻率和高饱和场。还发现，在单畴和一个 AF-APB 测量之间，温度相关的 MR 曲线的形状也有所不同，单畴的温度依赖性很强，而一个 AF-APB 的情况则与温度无关。我们认为这些观察结果表明，电子在 APB 上的输运发生了深刻的变化。所研究的 APB 缺陷会增加激活能并扰乱单畴 Fe(3)O(4)的长程电荷有序。
