Mesoscopic studies on photo- induced magnetic effects in magnetic semiconductors

磁性半导体光感磁效应的介观研究

• 批准号: 13650736
• 负责人: HASEGAWA Tetsuya
• 金额: $ 2.24万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2001
• 资助国家: 日本
• 起止时间: 2001 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13650736/
• 关键词: magnetic semiconductor; (Ga, Mn) As; scanning SQUID microscope; magnetic domain; stripe domain; photo-induced magnetism; (Ga, Mn)As

Diluted magnetic semiconductors (DMS) are key materials for spin electronics. However, their magnetic structures in a microscopic sense, which are important for applications, have been scarcely studied, so far. Here, we performed direct observations of magnetic domain structures in (Ga. Mn) As thin films, which is a typical DMS based on III-V semiconductors, with a thickness of t=1.0 and 0.2μm, by using a scanning SQUID microscope (SSM). For the t=0.2μm film, furthermore, we investigated the photo-irradiation effects on magnetic properties.(Ga. Mn) As thin films with in-plane magnetization were grown by the MBE technique at 25C. The Mn contents were 4.7% and 5.3% for t=1.0μm and t=0.2μm, films, respectively. SSM measurements were done at low temperatures ranging from 3K to 100K. The instrument senses the magnetic field perpendicular to the sample surface, Bz.From the SSM observations, we found anomalous circular domains for the t= 1.0μm film. The leakage field generated from the domain … More boundaries is weaker than the expectation, implying that multiple domains exist along the perpendicular direction. For the t=0.2μm film. In contrast, we observed ordinary stripe-shaped domains. The leakage field reached to 300μT, which is close to the calculated value. This tells us that the t=0.2μm film is composed of a single domain perpendicular to the film surface.Next, we have examined photo-induced effects on the t=0.2μm film. As a result, it was found that the Bz value under irradiation is approximately 1.2 times larger than the that before irradiation. The enhanced filed returned to the original one. But the reaction is substantially slow. At 3K, indeed, it took about 50min to reach to maximum. The reaction rate is decreased with increasing temperature. In addition, we confirmed that the rate is proportional to the intensity of light. In the present experiment, we observed, at the first time, that magnetism of (Ga, Mn) As can be enhanced by a relatively weak laser beam of 0.02mW/cm2. Less

稀释的磁性半导体（DMS）是自旋电子设备的关键材料。然而，到目前为止，它们从微观意义上来说很重要，它们对应用很重要。在这里，我们使用扫描鱿鱼显微镜（SSM）对（GA。MN）中的磁域结构进行了直接观察，它是薄膜，它是基于III-V半导体的典型DMS，其厚度为t = 1.0和0.2μm。对于t =0.2μm膜，我们研究了对磁性特性的光辐照作用。（GA。MN），因为MBE技术在25c时通过MBE技术生长了面内磁化的薄膜。 T =1.0μm和T =0.2μm的Mn含量分别为4.7％和5.3％。 SSM测量是在3K至100K的低温下进行的。该仪器会感觉到垂直于样品表面的磁场，BZ。从SSM观测值，我们发现T =1.0μm膜的异常圆形域。从域产生的泄漏场……更多的边界比期望弱，这意味着沿垂直方向存在多个域。对于t =0.2μm膜。相比之下，我们观察到了普通的条纹形状结构域。泄漏场达到300μt，接近计算的值。这告诉我们T =0.2μM膜由垂直于膜表面的单个域组成。接头，我们检查了对T =0.2μm膜的照片诱导的影响。结果，发现在照射下的Bz值大约是辐照前的Bz值约1.2倍。提起的增强归档返回到原始的。但是反应大大缓慢。实际上，在3K处，大约需要50分钟才能达到最大值。反应速率随温度升高而降低。此外，我们确认速率与光强度成正比。在演讲实验中，我们首次观察到（GA，MN）的磁性可以通过0.02MW/CM2的相对较弱的激光束增强。较少的

项目成果

福村知昭, 長谷川哲也: "走査型プローブ顕微鏡の磁性半導体及び超巨大磁気抵抗材料への適用"表面科学. 23. 233-238 (2002)

Tomoaki Fukumura、Tetsuya Hasekawa：“扫描探针显微镜在磁性半导体和超巨磁阻材料中的应用”《表面科学》23. 233-238 (2002)。

T.Fukumura, T.Shono, K.Inaba, T.Hasegawa, H.Koinuma, F.Matsuura, H.Ohono: "magnetic Domain Structure of a Ferromagnetic Semiconductor (Ga, Mn)As Observed with Scanning Prove Microscopes"Physica E. 10. 135-138 (2001)

T.Fukumura、T.Shono、K.Inaba、T.Hasekawa、H.Koinuma、F.Matsuura、H.Ohono：“用扫描证明显微镜观察到的铁磁半导体（Ga、Mn）的磁畴结构”Physica E

長谷川哲也: "走査SQUID顕微鏡の強磁性材料研究への応用"まてりあ. 41. 864-865 (2002)

Tetsuya Hasekawa：“扫描 SQUID 显微镜在铁磁材料研究中的应用”Materia。41. 864-865 (2002)

T.Fukumura, T.Shono, K.Inaba, T.Hasegawa, H.Koinuma, F.Matsuura, H.Ohono: "Magnetic Domain Structure of a Ferromagnetic Semiconductor (Ga,Mn)As Observed with Scanning Probe Microscopes"Physica E. 10. 135-138 (2001)

T.Fukumura、T.Shono、K.Inaba、T.Hasekawa、H.Koinuma、F.Matsuura、H.Ohono：“用扫描探针显微镜观察到的铁磁半导体 (Ga,Mn) 的磁畴结构”Physica E

T. Fukumura, T. Shono, K. Inaba, T. Hasegawa, H. Koinuma, F. Matsuura and H. Ohono,: "Magnetic Domain Structure of a Ferromagnetic Semiconductor (Ga, Mn) As Observed with Scanning Probe Microscopes"Physica E. 10. 135-138 (2001)

T. Fukumura、T. Shono、K. Inaba、T. Hasekawa、H. Koinuma、F. Matsuura 和 H. Ohono，：“用扫描探针显微镜观察到的铁磁半导体（Ga、Mn）的磁畴结构”Physica