Keavney D J, Wu D, Freeland J W, Johnston-Halperin E, Awschalom D D, Shi J
Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA.
Phys Rev Lett. 2003 Oct 31;91(18):187203. doi: 10.1103/PhysRevLett.91.187203.
We report induced Ga and As moments in ferromagnetic Ga(1-x)MnxAs detected using x-ray magnetic circular dichroism at the Mn, Ga, and As L(3,2) edges. Across a broad composition range, we find As and Ga dichroism signals which indicate an As 4s moment coupled antiparallel to the Mn 3d moment, and a smaller parallel Ga 4s moment. The Ga moment follows that of Mn in both doping and temperature dependence. These results are consistent with recent predictions of induced GaAs host moments and support the model of carrier-mediated ferromagnetic ordering involving As-derived valence band states.
我们报告了利用X射线磁圆二色性在Mn、Ga和As的L(3,2)边缘检测到的铁磁Ga(1-x)MnxAs中诱导的Ga和As磁矩。在很宽的成分范围内,我们发现As和Ga的二色性信号,这表明一个与Mn 3d磁矩反平行耦合的As 4s磁矩,以及一个较小的平行Ga 4s磁矩。Ga磁矩在掺杂和温度依赖性方面都与Mn磁矩一致。这些结果与最近关于诱导GaAs主体磁矩的预测一致,并支持涉及As衍生价带态的载流子介导铁磁有序模型。