Magnetoresistance and anomalous Hall effect in magnetic ZnO films
Magnetoresistance and anomalous Hall effect in magnetic ZnO films
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DOI：
10.1063/1.2715846
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发表时间：
2007-03
影响因子：
3.2
通讯作者：
Qingyu Xu;Lars Hartmann;H. Schmidt;H. Hochmuth;M. Lorenz;R. Schmidt‐Grund;C. Sturm;D. Spemann;M. Grundmann;Y. Liu
中科院分区：
文献类型：
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作者：
Qingyu Xu;Lars Hartmann;H. Schmidt;H. Hochmuth;M. Lorenz;R. Schmidt‐Grund;C. Sturm;D. Spemann;M. Grundmann;Y. Liu
采用脉冲激光沉积法在a面蓝宝石衬底上制备了n型导电的Co掺杂ZnO和Mn掺杂ZnO薄膜，并对其进行了磁输运测量，在低温下观察到了正的磁电阻效应。随着自由电子浓度n超过1019cm − 3，正MR急剧下降，并且对于Co掺杂的ZnO和Mn掺杂的ZnO，显示出几乎相同的对n的依赖性。这暗示了在两种类型的磁性ZnO膜中类似的S-D交换常数。对于Co掺杂的ZnO，饱和反常霍尔电阻率随电子浓度的降低而增大。在Mn掺杂的ZnO中没有观察到反常的霍尔效应。在自由电子近似下，正MR可能与导电电子由于s-d交换相互作用而产生的自旋极化有关。模型的导带自旋劈裂小于10meV。
Magnetotransport measurements were performed on n-type conducting Co-doped ZnO and Mn-doped ZnO films prepared by pulsed laser deposition on a-plane sapphire substrates, and positive magnetoresistance (MR) was observed at low temperature. The positive MR decreases drastically with the free electron concentration n exceeding 1019cm−3 and reveals almost the same dependency on n for Co-doped ZnO and Mn-doped ZnO. This hints towards a similar s-d exchange constant in both types of magnetic ZnO films. For Co-doped ZnO, the saturated anomalous Hall resistivity increases with decreasing electron concentration. No anomalous Hall effect was observed in Mn-doped ZnO. Within a free electron approximation the positive MR may be related with the spin polarization of conducting electrons due to s-d exchange interactions. The modeled spin splitting of the conduction band is smaller than 10meV.