Open AccessJournal Article
Zinc Vacancy induced magnetism in ZnO thin films and nanowires
Qian Wang,Qiang Sun,Puru Jena +2 more
TLDR
In this paper, it was shown that ZnO samples can be magnetic even without transition-metal doping and also suggests that introducing Zn vacancy is a natural and an effective way to fabricate magnetic ZNO nanostructures.Abstract:
Extensive calculations based on density functional theory have been carried out to understand the origin of magnetism in undoped ZnO thin films as found in recent experiments. The observed magnetism is confirmed to be due to Zn, instead of O, vacancy. The main source of the magnetic moment, however, arises from the unpaired 2p electrons at O sites surrounding the Zn vacancy with each nearest-neighbor O atom carrying a magnetic moment ranging from 0.490 to 0.740 B. Moreover, the study of vacancy-vacancy interactions indicates that in the ground state, the magnetic moments induced by Zn vacancies prefer to ferromagnetically couple with the antiferromagnetic state lying 44 meV higher in energy. Since this is larger than the thermal energy at room temperature, the ferromagnetic state can be stable against thermal fluctuations. Calculations and discussions are also extended to ZnO nanowires that have larger surface to volume ratio. Here, the Zn vacancies are found to lead to the ferromagnetic state too. The present theoretical study not only demonstrates that ZnO samples can be magnetic even without transition-metal doping but also suggests that introducing Zn vacancy is a natural and an effective way to fabricate magnetic ZnO nanostructures. In addition, vacancy mediated magnetic ZnO nanostructures may have certain advantages over transition-metal doped systems in biomedical applications.read more
Citations
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Journal ArticleDOI
The formation and detection techniques of oxygen vacancies in titanium oxide-based nanostructures.
Ayan Sarkar,Gobinda Gopal Khan +1 more
TL;DR: This review highlights different strategies for effectively introducing oxygen vacancies in titanium oxide-based nanomaterials, as well as a discussion on the positions of oxygen vacancies inside the TiO2 band gap based on theoretical calculations.
Journal ArticleDOI
Micro-Raman and XPS studies of pure ZnO ceramics
J. Das,Sangram K. Pradhan,Diptiranjan Sahu,Dilip Kumar Mishra,Sachindra Nath Sarangi,B.B. Nayak,Sarika Verma,B. K. Roul +7 more
TL;DR: In the absence of any magnetic impurity, the cause of room temperature ferromagnetic signal in the undoped system is attributed to various kinds of native defects such as oxygen vacancies (V O ) or zinc interstitials (I Zn ) and their clusters created inside the bulk ceramics during heating by slow step sintering schedule as mentioned in this paper.
Journal ArticleDOI
Size Dependence of Defect-Induced Room Temperature Ferromagnetism in Undoped ZnO Nanoparticles
TL;DR: In this paper, the intrinsic room-temperature ferromagnetic properties in undoped ZnO nanoparticles with different sizes synthesized by a wet chemical method at different temperatures were investigated.
Journal ArticleDOI
EXAFS and XANES analysis of oxides at the nanoscale
Alexei Kuzmin,Jesús Chaboy +1 more
TL;DR: The limits and possibilities of X-ray absorption near-edge spectroscopy in determining several effects associated with the nanocrystalline nature of materials are discussed in connection with the development of ZnO-based dilute magnetic semiconductors and iron oxide nanoparticles.
Journal ArticleDOI
Defect-induced magnetism in undoped wide band gap oxides: Zinc vacancies in ZnO as an example
Guozhong Xing,Yunhao Lu,Yufeng Tian,Jiabao Yi,Chjan C. Lim,Yongfeng Li,G. P. Li,Dandan Wang,B. Yao,Jun Ding,Yuan Ping Feng,Tom Wu +11 more
TL;DR: In this article, the authors carried out a comparative study on ZnO thin films prepared using both sol-gel and molecular beam epitaxy (MBE) methods, and they found that the solgel derived samples showed much stronger room temperature ferromagnetism with a magnetic signal persisting up to ∼740 K, and this ferromagnetic order coexists with a high density of defects in the form of zinc vacancies.
References
More filters
Journal ArticleDOI
The formation and detection techniques of oxygen vacancies in titanium oxide-based nanostructures.
Ayan Sarkar,Gobinda Gopal Khan +1 more
TL;DR: This review highlights different strategies for effectively introducing oxygen vacancies in titanium oxide-based nanomaterials, as well as a discussion on the positions of oxygen vacancies inside the TiO2 band gap based on theoretical calculations.
Journal ArticleDOI
Micro-Raman and XPS studies of pure ZnO ceramics
J. Das,Sangram K. Pradhan,Diptiranjan Sahu,Dilip Kumar Mishra,Sachindra Nath Sarangi,B.B. Nayak,Sarika Verma,B. K. Roul +7 more
TL;DR: In the absence of any magnetic impurity, the cause of room temperature ferromagnetic signal in the undoped system is attributed to various kinds of native defects such as oxygen vacancies (V O ) or zinc interstitials (I Zn ) and their clusters created inside the bulk ceramics during heating by slow step sintering schedule as mentioned in this paper.
Journal ArticleDOI
Size Dependence of Defect-Induced Room Temperature Ferromagnetism in Undoped ZnO Nanoparticles
TL;DR: In this paper, the intrinsic room-temperature ferromagnetic properties in undoped ZnO nanoparticles with different sizes synthesized by a wet chemical method at different temperatures were investigated.
Journal ArticleDOI
EXAFS and XANES analysis of oxides at the nanoscale
Alexei Kuzmin,Jesús Chaboy +1 more
TL;DR: The limits and possibilities of X-ray absorption near-edge spectroscopy in determining several effects associated with the nanocrystalline nature of materials are discussed in connection with the development of ZnO-based dilute magnetic semiconductors and iron oxide nanoparticles.
Journal ArticleDOI
Defect-induced magnetism in undoped wide band gap oxides: Zinc vacancies in ZnO as an example
Guozhong Xing,Yunhao Lu,Yufeng Tian,Jiabao Yi,Chjan C. Lim,Yongfeng Li,G. P. Li,Dandan Wang,B. Yao,Jun Ding,Yuan Ping Feng,Tom Wu +11 more
TL;DR: In this article, the authors carried out a comparative study on ZnO thin films prepared using both sol-gel and molecular beam epitaxy (MBE) methods, and they found that the solgel derived samples showed much stronger room temperature ferromagnetism with a magnetic signal persisting up to ∼740 K, and this ferromagnetic order coexists with a high density of defects in the form of zinc vacancies.