Photoemission studies of magnetic semiconductors

磁性半导体的光电发射研究

• 批准号: 14076209
• 负责人: FUJIMORI Atsushi
• 金额: $ 12.48万
• 依托单位: University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research on Priority Areas
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-14076209/
• 关键词: Magnetic semiconductors; Photoemission spectroscopy; Soft xjray magnetic circular dichroism; High-temperature ferromagnetism; Nano-struictures; 磁気伝導; 室温強磁性; 軌道混成

* Soft x-ray absorption (XAS) and soft x-ray magnetic circular dichroism (XMCD) studies at the Co 2p core absorption edges of Zn1-xCoxO (x=0.05) prepared by the pulsed laser deposition (PLD) method were performed and the obtained spectra were analyzed using cluster-model calculations. We have found that the temperature and the magnetic field dependences of the XMCD intensity were very different from non-interacting Co ions and that ferromagnetic and antiferromagnetic interactions between the Co ions coexist inhomogeneously.* XAS and resonance photoemission studies at the Mn 2p core absorption edges of Ga1-xMnxN prepared by the molecular-beam epitaxy (MBE) method were performed, and the obtained spectra were analyzed using cluster-model calculations. We found that the valence of the Mn ion was 2+ and that the Mn 3d states were largely distributed within the valence band of the GaN host. Acceptor levels formed by the Mn doping above the valence-band maximum Mn were found to be occupied b … More y electrons, indicating that the high-temperature ferromagnetism predicted by theory was nor realized because of the compensation effect.* XAS, XMCD and resonance photoemission studies were performed at the Cr 2p core absorption edges of Ga1-xCrxN (x=0.015). The Cr 2p XAS spectra indicated that the Cr was in the 3+ valence state. The Cr 3d partial density of states (PDOS) were largely distributed within the band gap of GaN, in striking contrast with Ga1-xMnxN. The Cr 3d PDOS was found to be suppressed at the Fermi level, and no Fermi-edge feature as predicted by band-structure calculations was observed.* XAS and XMCD measurements were made on Zn1-xVxO (x=0.05) which exhibited weak ferromagentism. The V ions substituting Zn2+ were found to be responsible for the magnetic properties. From comparison of the XMCD spectra with the magnetic susceptibility, we found that 10% of V ions were paramagnetic and 90 % were strongly coupled with each other antiferromagnetically. Furthermore, the paramagnetic V ions were found to be influenced by the axial crystal field of the hexagonal ZnO host. Less

* 利用软X射线吸收光谱（XAS）和软X射线磁性圆二色性光谱（XMCD）研究了脉冲激光沉积（PLD）法制备的Zn 1-xCoxO（x=0.05）的Co 2 p芯吸收边，并利用团簇模型计算对所得光谱进行了分析.我们发现，XMCD强度的温度和磁场依赖性与非相互作用的Co离子非常不同，并且Co离子之间的铁磁和反铁磁相互作用不均匀地共存。对分子束外延（MBE）法制备的Ga_（1-x）Mn_xN的Mn_（2 p）芯吸收边进行了X射线吸收光谱和共振光电子能谱研究，并用团簇模型计算对所得光谱进行了分析.我们发现Mn离子的价态为2+，并且Mn 3d态主要分布在GaN主体的价带内。发现Mn掺杂形成的受主能级在价带顶Mn以上被占据B ...更多信息 y电子，表明由于补偿效应，理论预测的高温铁磁性没有实现。XAS，XMCD和共振光电子能谱的研究进行了Cr的2 p核心吸收边的Ga 1-xCrxN（x=0.015）。Cr的2 p XAS谱表明Cr以3+价态存在。Cr的3d部分态密度（PDOS）主要分布在GaN的带隙内，与Ga 1-xMnxN形成鲜明对比。发现Cr 3d PDOS在费米能级被抑制，并且没有观察到带结构计算所预测的费米边缘特征。对Zn_（1-x）O（x=0.05）样品进行了XAS和XMCD测量。V离子取代Zn ~（2+）是导致磁性的主要原因。从比较的XMCD光谱与磁化率，我们发现，10%的V离子是顺磁性和90%的强烈相互耦合的反铁磁性。此外，还发现顺磁V离子受到六方ZnO主体轴向晶场的影响。少

项目成果

Photoemission and Core-Magnetic Circular Dichroism Studies of Diluted Magnetic Semiconductors

稀磁半导体的光电发射和核磁圆二色性研究

• 发表时间: 2005
• 期刊: J. Electron Spectrosc. Relat. Phenom. 144-147
• 作者: A.Fujimori;J.Okabayashi;Y.Takeda;T.Mizokawa;J.Okamoto;K.Mamiya;Y.Saitoh;Y.Muramatsu;M.Oshima;S.Ohya;M.Tanaka
• 通讯作者: M.Tanaka

Photoemission and Core-Level Magnetic Circular Dichroism Studies of Diluted Magnetic Semiconductors

稀磁半导体的光电发射和核心级磁圆二色性研究

• 发表时间: 2005
• 期刊: J. Electron Spectrosc. Relat. Phenom 144-147
• 作者: A.Fujimori;J.Okabayashi;Y.Takeda;T.Mizokawa;J.Okamoto;K.Mamiya;Y.Saitoh;Y.Muramatsu;M.Oshima;S.Ohya;M.Tanaka
• 通讯作者: M.Tanaka

Novel Spingtronic Materials Based on Ferromagnetic Semiconductor Chalcopyrites

基于铁磁半导体黄铜矿的新型自旋电子材料

• 发表时间: 2004
• 期刊: Interntl. J. Nanoscience 3
• 作者: G.A.Medvedkin;S.I.Goloshchapov;V.G.Voevodin;K.Sato;T.Ishibashi;S.Mitani;K.Takanashi;A.Fujimori;Y.Ishida;J.Okabayashi;D.D.Sarma
• 通讯作者: D.D.Sarma

Characterization of magnetic components in the diluted magnetic semiconductor Zn 1-x Co x O by x-ray magnetic circular dichroism

• DOI: 10.1103/physrevb.72.201201
• 发表时间: 2005-05
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: M. Kobayashi;Y. Ishida;J. Hwang;T. Mizokawa;A. Fujimori;K. Mamiya;J. Okamoto;Y. Takeda;T. Okane;Y. Saitoh;Y. Muramatsu;A. Tanaka;H. Saeki;H. Tabata;T. Kawai

In situphotoemission study of the room-temperature ferromagnet ZnGeP_2:Mn

室温铁磁体ZnGeP_2:Mn的原位光发射研究

• 发表时间: 2003
• 期刊: Phys.Rev Lett 91・10
• 作者: H.Isshiki;Adachi Noboru;佐藤 勝昭
• 通讯作者: 佐藤 勝昭