锑化物磁性半导体体材料研究

利用布里奇曼法进行GaMnSb磁性半导体生长，并对其结构、磁学及电学特性进行研究.在高Mn区域发现了室温铁磁性，而在低Mn区域只探测到抗磁信号.电学测量表明，两个区域的空穴浓度基本相当，说明观察到的磁学性能差异与载流子浓度无关.X射线能谱测试显示，高Mn区域的Mn组分分布不均匀，低Mn区域的Mn组分分布则相对更为均匀.此外，高Mn区域的饱和磁化强度仅为每Mn原子0.013μ_B，与理论值相差约两个数量级.X射线衍射谱的结果说明，高Mn区域有出现MnSb第二相的迹象.以上结果证实所观察到的室温铁磁性并不是GaMnSb的内禀特性.

Properties of Bulk Antimonide-based Magnetic Semiconductors

By using the Bridgeman method, the growth of GaMnSb bulk materials and their structural, magnetic and electric characterizations are reported. Room-temperature ferromagnetic signals were observed at the Mn-rich regions, whereas the Mn-deficient areas exhibit diamagnetism. The saturated magnetization in the Mn-rich areas is merely 0.013μ_B per Mn atom, which is far lower than the theoretical value. Electric measurements show that these two regions almost have identical hole concentrations, which indicates that the difference in the magnetic behaviors is not correlated with the carrier concentration. The characterizations by energy-dispersive X-ray spectroscopy demonstrate that the distribution of Mn atoms is more uniform in the Mn-poor regions than that in the Mn-rich regions. Moreover, the X-ray diffraction measurements reveal the appearance of MnSb impurity phase in the Mn-rich regions. All these results show that the ferromagnetism observed here is extrinsic.