Ferromagnetic properties of IV–VI diluted magnetic semiconductor Ge1−xMnxTe films prepared by radio frequency sputtering
Ferromagnetic properties of IV–VI diluted magnetic semiconductor Ge1−xMnxTe films prepared by radio frequency sputtering
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DOI：
10.1063/1.1555697
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发表时间：
2003-03
影响因子：
3.2
通讯作者：
Y. Fukuma;H. Asada;N. Nishimura;T. Koyanagi
中科院分区：
文献类型：
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作者：
Y. Fukuma;H. Asada;N. Nishimura;T. Koyanagi
采用射频溅射法在玻璃衬底上制备了锰含量高达x=0.53的IV-VI稀释磁性半导体Ge1−xMnxTe薄膜。磁性测量表明，所有的Ge1−xMnxTe薄膜（0.07≤x≤053）在低温下都表现出铁磁有序，因为可以清楚地观察到迟滞行为。在4.2 K的自发磁化条件下，Mn离子的有效自旋Seff小于1.0，表明Mn离子是部分铁磁排列的。Seff的值取决于载流子浓度和Mn的组成。因此，Ge1−xMnxTe薄膜的磁性顺序是由铁磁Ruderman-Kittel-Kasuya-Yosida （RKKY）相互作用和反铁磁超交换机制之间的竞争引起的。基于平均场近似的居里温度随着Mn成分的增加而线性增加，直到x=0.3，并且在此点以上趋于80 K左右饱和。基于一个简单的RKKY机制，自旋交换…
IV–VI diluted magnetic semiconductor Ge1−xMnxTe films with various Mn compositions up to x=0.53 were prepared on glass substrates by a rf sputtering method. Magnetic measurements indicate that all the Ge1−xMnxTe films (0.07⩽x⩽053) show ferromagnetic order at low temperatures since hysteretic behavior is clearly observed. The effective spin Seff’s of Mn ions deduced from the spontaneous magnetization at 4.2 K are less than 1.0, indicating that Mn ions are partially aligned ferromagnetically. The value of the Seff depends on the carrier concentration as well as the Mn composition. The magnetic order of the Ge1−xMnxTe films is thus caused by the competition between the ferromagnetic Ruderman–Kittel–Kasuya–Yosida (RKKY) interaction and the antiferromagnetic superexchange mechanism. The Curie temperature based on the mean field approximation increases linearly with increasing Mn composition up to x=0.3 and above this point tends to saturate around 80 K. On the basis of a simple RKKY mechanism, the spin exchang...