Ferromagnetism in ZnO Nanowires Derived from Electro‐deposition on AAO Template and Subsequent Oxidation

Yi, Jiabao; Pan, Hui; Lin, Jianyi; Ding, Jun; Feng, Yuan Ping; Thongmee, Sirikanjana; Liu, T.; Gong, Hao; Wang, Lin-Lin

doi:10.1002/adma.200702387

Cited by 141 publications

(88 citation statements)

References 45 publications

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“…26 However, it is quite comparable to the calculated M S of 0.069−0.34 emu/g obtained based on our first principles calculation discussed earlier, assuming the magnetic moment of 0.001−0.005 μ B /atom depending on the thickness of the nanoplates as in Table 1. Alternatively, it was reported by Yi et al 27 that the presence of very small Zn clusters embedded in ZnO matrix may lead to the measurable magnetic moment in ZnO. The magnitude of moment was comparable to the M S of the nanoplates in the present work.…”

supporting

confidence: 82%

Magnetism in Dopant-Free ZnO Nanoplates

et al. 2012

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It is known that bulk ZnO is a nonmagnetic material. However, the electronic band structure of ZnO is severely distorted when the ZnO is in the shape of a very thin plate with its dimension along the c-axis reduced to a few nanometers while keeping the bulk scale sizes in the other two dimensions. We found that the chemically synthesized ZnO nanoplates exhibit magnetism even at room temperature. First-principles calculations show a growing asymmetry in the spin distribution within the distorted bands formed from Zn (3d) and O (2p) orbitals with the reduction of thickness of the ZnO nanoplates, which is suggested to be responsible for the observed magnetism. In contrast, reducing the dimension along the a-or b-axes of a ZnO crystal does not yield any magnetism for ZnO nanowires that grow along c-axis, suggesting that the internal electric field produced by the large {0001} polar surfaces of the nanoplates may be responsible for the distorted electronic band structures of thin ZnO nanoplates.

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confidence: 82%

Magnetism in Dopant-Free ZnO Nanoplates

et al. 2012

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“…10 However, the defects responsible for the observed ferromagnetism in nondoped ZnO are still under debate. Zn defects, [3][4][5] O vacancies, 6,7 and Zn nanoclusters embedded in ZnO matrix, 8 have been considered to be the possible origin. Theoretically, O interstitial, Zn vacancy and O vacancy (V O ) clusters have been suggested to induce the ferromagnetism in ZnO.…”

confidence: 99%

“…Room temperature ferromagnetism has been observed in the traditionally nonmagnetic semiconductor oxide nanoparticles and films, such as ZnO, CeO 2 , Al 2 O 3 , In 2 O 3 , HfO 2 , and SnO 2 , etc., and the defects have generally been considered to be the origin. [1][2][3][4][5][6][7][8] ZnO is a wide band gap semiconductor (E g ∼ 3.3 eV at 300 K) and has a large exciton binding energy (∼ 60 meV), which has wide applications in optoelectronics.…”

mentioning

confidence: 99%

Room temperature ferromagnetism in ZnO prepared by microemulsion

Wen

Zhang

et al. 2011

AIP Advances

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Clear room temperature ferromagnetism has been observed in ZnO powders prepared by microemulsion. The O vacancy (VO) clusters mediated by the VO with one electron (F center) contributed to the ferromagnetism, while the isolated F centers contributed to the low temperature paramagnetism. Annealing in H2 incorporated interstitial H (Hi) in ZnO, and removed the isolated F centers, leading to the suppression of the paramagnetism. The ferromagnetism has been considered to originate from the VO clusters mediated by the Hi, leading to the enhancement of the coercivity. The ferromagnetism disappeared after annealing in air due to the reduction of Hi

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“…The observed reduction of the saturation moment at higher field is due to dominance of the diamagnetic contribution from the AAO template. Similar RTFM in different oxides like ZnO, HfO 2 , SnO 2 , TiO 2 nanostructures is also observed in which structural defects like oxygen vacancies [2 6], cation vacancies [8], grain boundaries or interfacial defects [2,9] are attributed to the origin of FM. Therefore to investigate the possible defects formation within the SnO 2 NWs here, PL spectroscopic measurements are performed using the excitation wavelength of 330 nm of Xe lamp.…”

Section: Origin Of Ferromagnetism In Sno 2 Nwsmentioning

confidence: 62%

“…However the origin of such unexpected FM in different oxides is found to be controversial issue [2][3][4][5][6][7][8]. RTFM in the nanostructures and thin films of undoped and non magnetic ion doped oxide semiconductors is attributed to different intrinsic structural defects like oxygen vacancies [2,5,6], cation vacancies [8] or even the surface defects [9], where the quantum confined dimensions of the nanostructures should have very important influence [2]. Therefore, the study of the origin RTFM and the tuning of the ferromagnetic properties in the pristine and non magnetic ion doped metal oxide semiconductors are very exciting considering their potential application for modern spintrionic and opto-spintronic devices.…”

Section: Introductionmentioning

confidence: 99%

d⁰Ferromagnetism in Oxide Nanowires: Role of Intrinsic Defects

Ghosh

Khan

Mandal

2013

EPJ Web of Conferences

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Abstract. In this report, we have investigated the origin of defect-induced room-temperature d 0 ferromagnetism in pure SnO 2 and ZnO nanowires (NWs) with average diameter ~ 50 nm, prepared by template assisted route. Photoluminescence (PL) and electron paramagnetic resonance (EPR) spectroscopic measurements show the singly ionized oxygen vacancy is inducing ferromagnetism in pure SnO 2 NWs whereas cation (Zn) vacancy is found to responsible for the ferromagnetic behaviour in pure ZnO NWs. Besides, it is found that the Zn vacancy-induced ferromagnetism in ZnO can be tuned by substituting few percentage of nonmagnetic alkali metal like potassium (K) at Zn site. Saturation moment as well as Curie temperature has found to increase significantly with K-doping up to 4 at.% but a decrease of ferromagnetic response is observed for higher K-doping. X-ray photoelectron spectra show that K +1 ions substitute at Zn site and thus introduce hole through which a ferromagnetic interaction between Zn vacancies can be mediated. The direct correlation between the Zn vacancy concentration and the corresponding saturation moment indicates that Zn vacancyinduced ferromagnetism in ZnO can be successfully tuned by K-doping that can an exciting approach to prepare ZnO-based dilute magnetic semiconductors for modern spintronic technology.

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Ferromagnetism in ZnO Nanowires Derived from Electro‐deposition on AAO Template and Subsequent Oxidation

Cited by 141 publications

References 45 publications

Magnetism in Dopant-Free ZnO Nanoplates

Magnetism in Dopant-Free ZnO Nanoplates

Room temperature ferromagnetism in ZnO prepared by microemulsion

d⁰Ferromagnetism in Oxide Nanowires: Role of Intrinsic Defects

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Ferromagnetism in ZnO Nanowires Derived from Electro‐deposition on AAO Template and Subsequent Oxidation

Cited by 141 publications

References 45 publications

Magnetism in Dopant-Free ZnO Nanoplates

Magnetism in Dopant-Free ZnO Nanoplates

Room temperature ferromagnetism in ZnO prepared by microemulsion

d0Ferromagnetism in Oxide Nanowires: Role of Intrinsic Defects

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d⁰Ferromagnetism in Oxide Nanowires: Role of Intrinsic Defects