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Vacancy-induced magnetism in metal oxides or nitrides probed by spin-polarized positron beam
https://repo.qst.go.jp/records/72707
https://repo.qst.go.jp/records/72707d0498e6d-f0c1-4b1a-8bd2-bc3df50957fb
| Item type | 会議発表用資料 / Presentation(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2018-03-19 | |||||
| タイトル | ||||||
| タイトル | Vacancy-induced magnetism in metal oxides or nitrides probed by spin-polarized positron beam | |||||
| 言語 | ||||||
| 言語 | eng | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_c94f | |||||
| 資源タイプ | conference object | |||||
| アクセス権 | ||||||
| アクセス権 | metadata only access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||
| 著者 |
前川, 雅樹
× 前川, 雅樹× 境, 誠司× 和田, 健× 宮下, 敦巳× 河裾, 厚男× 前川 雅樹× 境 誠司× 和田 健× 宮下 敦巳× 河裾 厚男 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | Some semiconductor materials of metal oxides or nitrides, such as zinc oxide (ZnO) or gallium nitride (GaN), exhibit d0 ferromagnetism, which may be induced by lattice defects. From theoretical calculations, cation vacancies are the most probable sources of d0 ferromagnetism. However, conventional measurement techniques hardly demonstrate directly that cation vacancies act as ferromagnetic centers. Spin-polarized positron annihilation spectroscopy (SP-PAS) is a unique technique, which can detect magnetic moments associated with vacancies. From the magnetic Doppler-broadening (MDB) spectrum, magnetic moments at vacancies can be detected. In this study, we attempted to detect vacancy-induced magnetism in ZnO and GaN by the SP-PAS method. To create vacancies, oxygen and nitrogen ions were implanted to the undoped ZnO and p-type GaN crystal, respectively. The range of ion implantation was estimated to be 100 nm from the surface. The magnetization curves obtained at 30 K using SQUID measurement show the induced ferromagnetism upon implantation. The MDB spectra were measured in the magnetic field of ±0.91 T at 30K. For unimplanted state, the intensity of MDB spectra are nearly null, suggesting the lack of magnetic moments at vacancies. By implantation, finite MDB intensities appear in both samples. Also, the MDB spectrum shapes were theoretically reproduced assuming cation vacancies. These confirm the existence of magnetic moments at cation vacancies and those are the source of the ferromagnetism observed by SQUID. |
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| 会議概要（会議名, 開催地, 会期, 主催者等） | ||||||
| 内容記述タイプ | Other | |||||
| 内容記述 | ISSS-8国際会議参加・発表のため | |||||
| 発表年月日 | ||||||
| 日付 | 2017-10-26 | |||||
| 日付タイプ | Issued | |||||
