Ferromagnetism in pure wurtzite zinc oxide

Zuo, Xu; Yoon, S. D.; Yang, Aria; Duan, Wenhui; Vittoria, C.; Harris, Vincent G.

doi:10.1063/1.3062822

Cited by 90 publications

(39 citation statements)

References 14 publications

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“…[1][2][3][4][5][6][7][8][9][10][11] The reported variations in the results and conclusions are quite controversial; however, it seems the magnetism observed in oxide nanoparticles may be affected by particle size, grain boundary area, defects, surfactant coating and/or doping. 9,10,[12][13][14][15] Upon revisiting samples which had been previously prepared, we noted that the estimated crystallite size had increased after several years. Prompted by our previous observation of an inverse relationship between particle size and magnetization 15 , we re-measured the magnetic properties of a number of aged samples and found many variable results.…”

Section: Introductionmentioning

confidence: 99%

Unusual crystallite growth and modification of ferromagnetism due to aging in pure and doped ZnO nanoparticles

Thurber

Alanko

Beausoleil

et al. 2012

Journal of Applied Physics

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We report the unusual growth of pure and Fe doped ZnO nanoparticles prepared by forced hydrolysis, and the weakening of ferromagnetism due to aging in ambient conditions. More than four dozen nanoparticle samples in the size range of 4 -20 nm were studied over 1 to 4 years. The as-prepared samples had significant changes in their crystallite sizes and magnetization as they aged in ambient conditions. Detailed studies using x-ray diffraction and transmission electron microscopy (TEM) demonstrated that the crystallite size increased by as much as 1.4 times. Lattice parameters and strain also showed interesting changes. Magnetometry studies of Zn 1-x Fe x O with x = 0-0.2 showed ferromagnetism at room temperature; however, keeping the samples in ambient conditions for one year resulted in modifications in the crystallite size and magnetization. For the Zn 0.95 Fe 0.05 O sample, the size changed from 7.9 nm to 9.0 nm, while the magnetization decreased from 1 memu/g to 0.2 memu/g . Both magnetic and structural changes due to aging varied with the environment in which they were stored, indicating that these changes are related to the aging conditions.

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Section: Introductionmentioning

confidence: 99%

Unusual crystallite growth and modification of ferromagnetism due to aging in pure and doped ZnO nanoparticles

Thurber

Alanko

Beausoleil

et al. 2012

Journal of Applied Physics

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“…Theoretically, stability of high spin configurations was first analyzed for V Si in SiC [15][16][17][18]. Subsequent first principles calculations predicted stability of high spin state of neutral V cation in CaO [7,9], HfO 2 [9,19,20], III-V nitrides [21][22][23][24][25], MgO [24,26], ZnO [22,25,27,28] and in II-VI compounds [29]. In this paper we study high spin states of V cation by firstprinciples calculations [30,31].…”

Section: Introductionmentioning

confidence: 99%

High-spin states of cation vacancies in GaP, GaN, AlN, BN, ZnO, and BeO: A first-principles study

Volnianska

Bogusławski

2011

Phys. Rev. B

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High spin states of cation vacancies in GaP, GaN, AlN, BN, ZnO and BeO were analyzed by first principles calculations. The spin-polarized vacancy-induced level is located in the band gap in GaP, ZnO and BeO. In the nitrides, the stronger exchange coupling forces the vacancy states to be resonant with valence bands, forbids formation of positively charged vacancies in GaN and BN, and allows Al vacancy in p-AlN to assume the highest possible S=2 spin state. The shape of the spin density, isotropic in the zinc blende structure, has a pronounced directional character in the wurtzite structure. Stability of spin polarization of the vacancy states is determined by spin polarization energies of anions, as well as by interatomic distances between the vacancy neighbors, and thus is given by both the lattice constant of the host and the atomic relaxations around the vacancy. Implications for experiment are discussed.

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“…It challenges the mJ paradigm for magnetism, where m refers the local moment and J stands for the interaction between the local moments. Experimentally, defect-induced ferromagnetism was observed in many materials, including graphite [2][3][4][5] and various oxides [6][7][8][9][10][11][12]. SiC single crystals are emerging as another candidate for this investigation and have been shown to be ferromagnetic after particle irradiation [13,14] or after aluminum doping [15].…”

Section: Introductionmentioning

confidence: 99%

Structural and magnetic properties of irradiated SiC

Wang

Chen

et al. 2014

Journal of Applied Physics

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Abstract:We present a comprehensive structural characterization of ferromagnetic SiC single crystals induced by Ne ion irradiation. The ferromagnetism has been confirmed by electron spin resonance and possible transition metal impurities can be excluded to be the origin of the observed ferromagnetism. Using X-ray diffraction and Rutherford backscattering/channeling spectroscopy, we estimate the damage to the crystallinity of SiC which mutually influences the ferromagnetism in SiC.

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Ferromagnetism in pure wurtzite zinc oxide

Cited by 90 publications

References 14 publications

Unusual crystallite growth and modification of ferromagnetism due to aging in pure and doped ZnO nanoparticles

Unusual crystallite growth and modification of ferromagnetism due to aging in pure and doped ZnO nanoparticles

High-spin states of cation vacancies in GaP, GaN, AlN, BN, ZnO, and BeO: A first-principles study

Structural and magnetic properties of irradiated SiC

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