Growth and Characterization of Diluted Magnetic III-V Compound Semiconductors

稀磁 III-V 化合物半导体的生长和表征

基本信息

批准号：
02452142
负责人：
OHNO Hideo
金额：
$ 4.54万
依托单位：
Hokkaido University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

项目摘要

Molecular beam epitaxial (MBE) growth and electric and magnetic properties of diluted magnetic III-V semiconductors, especially (In, Mn) As, are studied. Following is a summary of the research results. Molecular Beam Epitaxial Growth : Maximum Mn concentration that can be incorporated into InAs lattice without having second phase (which is MnAs) is critically dependent on the growth temperature during MBE growth. At 300ﾟC, x (in In_<1-x>Mn_xAs) has to be<0.03 and the conduction is p-type whereas at 200ﾟC, x<0.25 and n-type.Characterization of Epitaxial layers : (1) Magnetism All n-type samples are paramagnetic and the direct interaction between Mn ions is antiferromagnetic with nearest neighbor J of -1.6 K. All p-type samples are paramagnetic at medium to high temperatures, but show spontaneous magnetization at low temperatures. Paramagnetic component which saturates only at high magnetic fields (4 to 9 T) is also present. The spontaneous magnetization makes up for 25 % of saturation m … More agnetization at the lowest temperature (1.4K) investigated. (2) Electrical Properties n-type samples show negative magnetoresistance at low temperatures. No hysteresis is observed. The Hall resistance of p-type samples is dominated by anomalous Hall effect. At temperatures below 7.5 K, hysteresis appears in B dependence of Hall resistance together with negative magnetoresistance extending to high magnetic fields. Hysteresis is only observed in p-type samples. This can be explained by the presence of large magnetic polarons with canted spins inside. The origin of the canting is believed to be the exchange interaction between holes and Mn ions. The interaction is mostly ferromagnetic with spin texture (i. e. canting) due to spin-orbit interaction of to Mn-Mn antiferromagnetic interaction. Rotation of polarons gives rise to the spontaneous magnetization, whereas the alignment of spins with high magnetic fields results in paramagnetic response at high fields. This is the first observation of weak ferromagnetism due to localized carrier-spin exchange in diluted magnetic semiconductors. Less

稀释的磁性III-V半导体的分子束外延（MBE）生长以及电和磁性能，尤其是（IN，MN）AS，是研究的。以下是研究结果的摘要。分子束外延生长：可以将其掺入INAS晶格中的最大MN浓度（即MNA）在MBE生长过程中严重取决于生长温度。在300ﾟC时，x（in_ <1-x> mn_xas）必须<0.03，传导为p型，而在200 c，x <0.25和n型中，外延层的特征。 -1.6 K.所有P型样品在中等温度至高温下都是顺磁性，但在低温下显示自发磁化。也存在仅在高磁场（4至9 t）饱和的顺磁分量。赞助磁化量占饱和度的25％……在研究的最低温度（1.4K）下进行了更多的治疗。（2）电特性N型样品在低温下显示出负磁度。未观察到滞后。 P型样品的大厅电阻以异常的大厅效应为主。在低于7.5 K的温度下，滞后在霍尔电阻的B依赖性中出现，负磁场延伸至高磁场。仅在P型样品中观察到滞后。这可以通过内部有倾斜旋转的大型磁性极性子的存在来解释。倾斜的起源被认为是孔和Mn离子之间的交换相互作用。由于与MN-MN抗铁磁相互作用的自旋轨道相互作用，这种相互作用主要是与自旋纹理（即canting）的铁磁相互作用。极性的旋转产生了赞助磁化，而具有高磁场的自旋对齐会导致高场在高场的顺磁反应。这是由于稀释的磁性半导体中局部载体旋转交换而引起的弱铁磁作观察。较少的