Structural, magnetic, and magnetotransport properties of Mn-Si films synthesized on a 4H-SiC(0001) wafer
Structural, magnetic, and magnetotransport properties of Mn-Si films synthesized on a 4H-SiC(0001) wafer
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DOI：
10.1103/physrevb.75.165323
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发表时间：
2007-04
影响因子：
3.7
通讯作者：
Wenhong Wang;F. Takano;H. Akinaga;H. Ofuchi
中科院分区：
文献类型：
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作者：
Wenhong Wang;F. Takano;H. Akinaga;H. Ofuchi
本文研究了用退火法在4H-SiC(0001)衬底上制备的Mn-Si薄膜的结构、磁性和磁输运性质。磁和荧光X射线吸收精细结构测量表明，样品由两个不耦合的磁相组成：一个是顶部合成的Mn-Si层，居里温度在300K左右，磁各向异性；另一个是Mn原子，它只存在于界面的4H-SiC晶格中的间隙位上，并在2K以下表现出类似超顺磁性的行为。磁阻(MR)表现出有趣的温度和场相关行为。当温度高于100K时，样品只表现出正的MR，当温度低于100K时，出现负的MR。有趣的是，在100K的中温下，随着磁场的增加，磁流变仪出现了由负到正的符号反转。讨论了正负磁阻的可能来源。此外，我们还发现，在2~100K温度范围内，霍尔效应是由侧跃引起的反常霍尔效应(AHE)主导的。然而，在高于100K的温度下，AHE既不能用歪散射描述，也不能用侧跳更多的机制来描述。
We present a comprehensive study of the structural, magnetic, and magnetotransport properties of Mn-Si films synthesized on a 4H-SiC(0001) wafer by an annealing method. Magnetic- and fluorescence-extended x-ray-absorption fine-structure measurements reveal that the sample comprises two uncoupled magnetic phases: one is the top synthesized Mn-Si layer, which displays a Curie temperature around 300 K and magnetic anisotropy; the other one is Mn atoms, which solely incorporate on the interstitial site in the 4H-SiC lattice in the interface and show superparamagnetismlike behavior with a blocking temperature below 2 K. The magnetoresistance (MR) exhibits an interesting temperature- and field-dependent behavior. At temperatures above 100 K, the sample only exhibits a positive MR. At temperatures below 100 K, a negative MR prevails. Interestingly, at intermediate temperature of 100 K, with increasing magnetic field, a sign inversion of the MR from negative to positive is observed. The possible origin of the positive and negative MR is discussed. Furthermore, we found that the Hall effect is dominated by an anomalous Hall effect (AHE) due to side jumps at temperatures between 2 K and 100 K. However, at temperatures higher than 100 K, the AHE cannot be described with either a skew scattering or side jumpsmore » mechanism.« less