Role of point defects in room-temperature ferromagnetism of Cr-doped ZnO

Liu, Hui; Zhang, Xiao; Li, Luyan; Wang, Y. X.; Gao, Kuang-Hong; Li, Z. Q.; Zheng, Rongkun; Ringer, Simon P.; Zhang, Bei; Zhang, X. X.

doi:10.1063/1.2772176

Cited by 158 publications

(52 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The weak UV luminescence peak located at ~ 386 nm, corresponding to a photon energy of ~ 3.21 eV, is related to near band edge emission. Other peaks are found in the visible blue spectral region via the fitting of the entire emission at energies of 3.00 eV, 8 2.84 eV, 2.67 eV and 2.55 eV which may correspond to V Zn , Zn i , V Zn -and V o , respectively, which are in good agreement with other studies in the literature [32,33]. [34].…”

Section: Resultssupporting

confidence: 81%

“…by binding the spins of magnetic ions to form bound magnetic polarons, consistent with the hypothesis that such defects may be the origin of the observed room temperature ferromagnetism [32,33,45].…”

Section: Resultssupporting

confidence: 70%

“…For example, Yan et al pointed out that oxygen vacancies play an important role in the appearance of room temperature ferromagnetism for Mn-doped ZnO nanorods [46]. Liu et al [32] indicated that point defects such as Zn i or V Zn are responsible for ferromagnetism in Cr:ZnO samples and Hong et al [47] have pointed out that the magnetization in their Cr:ZnO films is related to oxygen vacancies (V o ). Furthermore, Liu et al [48] suggested that two key factors lead to the appearance of ferromagnetism in TM-doped ZnO nanocrystals: one is the increase of the number of defects and oxygen vacancies, the other is the exchange interactions between the TM ions and the O ion spin moment.…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

Structural, optical and magnetic properties of Ni-doped ZnO micro-rods grown by the spray pyrolysis method

Yılmaz

McGlynn

Bacaksız

et al. 2012

Chemical Physics Letters

View full text Add to dashboard Cite

Undoped and Ni-doped ZnO micro-rod arrays were successfully synthesized by the spray pyrolysis method on glass substrates. Analysis of the samples with x-ray diffraction and scanning electron microscopy showed that these micro-rod arrays had a polycrystalline wurtzite structure with a highly c-axis preferred orientation. Photoluminescence studies at both 300 K and 10 K show that the incorporation of nickel leads to a relative increase in the visible blue light band intensity. Magnetic measurements indicated that Ni-doped ZnO samples exhibit ferromagnetic behavior at room temperature, which is possibly related to the presence of point defects.

show abstract

Section: Resultssupporting

confidence: 81%

Section: Resultssupporting

confidence: 70%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Structural, optical and magnetic properties of Ni-doped ZnO micro-rods grown by the spray pyrolysis method

Yılmaz

McGlynn

Bacaksız

et al. 2012

Chemical Physics Letters

View full text Add to dashboard Cite

show abstract

“…Considerable efforts have been made to characterize and describe the physical and chemical properties of metal oxide nanomaterials because of their significant applications in numerous technological fields. [1][2][3][4] The oxides of transition metals are an important class of semiconductors that have wider applications in magnetic storage media, solar energy transformation, electronics, and catalysis. [5][6][7][8][9][10][11][12] Among various transition metal oxides, copper oxide (CuO) has attracted greater attention due to its fascinating properties such as the basis of high critical temperature (T c ) superconductors.…”

Section: Introductionmentioning

confidence: 99%

Size-dependent antimicrobial properties of CuO nanoparticles against Gram-positive and -negative bacterial strains

Azam

Ahmed²,

Oves³

et al. 2012

IJN

699

237

View full text Add to dashboard Cite

Background: CuO is one of the most important transition metal oxides due to its captivating properties. It is used in various technological applications such as high critical temperature superconductors, gas sensors, in photoconductive applications, and so on. Recently, it has been used as an antimicrobial agent against various bacterial species. Here we synthesized different sized CuO nanoparticles and explored the size-dependent antibacterial activity of each CuO nanoparticles preparation. Methods: CuO nanoparticles were synthesized using a gel combustion method. In this approach, cupric nitrate trihydrate and citric acid were dissolved in distilled water with a molar ratio of 1:1. The resulting solution was stirred at 100°C, until gel was formed. The gel was allowed to burn at 200°C to obtain amorphous powder, which was further annealed at different temperatures to obtain different size CuO nanoparticles. We then tested the antibacterial properties using well diffusion, minimum inhibitory concentration, and minimum bactericidal concentration methods. Results: XRD spectra confirmed the formation of single phase CuO nanoparticles. Crystallite size was found to increase with an increase in annealing temperature due to atomic diffusion. A minimum crystallite size of 20 nm was observed in the case of CuO nanoparticles annealed at 400°C. Transmission electron microscopy results corroborate well with XRD results. All CuO nanoparticles exhibited inhibitory effects against both Gram-positive and -negative bacteria. The size of the particles was correlated with its antibacterial activity. Conclusion: The antibacterial activity of CuO nanoparticles was found to be size-dependent. In addition, the highly stable minimum-sized monodispersed copper oxide nanoparticles synthesized during this study demonstrated a significant increase in antibacterial activities against both Gram-positive and -negative bacterial strains.

show abstract

“…For example, Hsu et al 65 have performed x-ray near edge spectroscopy on Co-doped ZnO films and shown that the enhancement in ferromagnetism is directly related to an increase in oxygen vacancies. Liu et al 66 indicated that point defects such as Zn i or V Zn are responsible for ferromagnetism in Cr:ZnO samples. Furthermore, Liu et al 67 suggested that two key factors lead to the appearance of ferromagnetism in TMdoped ZnO nanocrystals: one is the increase of the number of defects and oxygen vacancies and the other is the exchange interactions between the TM ions and the O ion spin moment.…”

Section: Resultsmentioning

confidence: 99%

Effects of Cu diffusion-doping on structural, optical, and magnetic properties of ZnO nanorod arrays grown by vapor phase transport method

Yılmaz¹,

McGlynn²,

Bacaksız³

et al. 2012

Journal of Applied Physics

View full text Add to dashboard Cite

Realization of a 33 GHz phononic crystal fabricated in a freestanding membrane AIP Advances 1, 042001 (2011) Preparation of uncapped CdSe1xSx semiconducting nanocrystals by mechanical alloying J. Appl. Phys. 110, 124306 (2011) Formation mechanisms of spatially-directed zincblende gallium nitride nanocrystals J. Appl. Phys. 110, 124307 (2011) Surface modification of monocrystalline zinc oxide induced by high-density electronic excitation J. Appl. Phys. 110, 124310 (2011) Investigation of poly(o-anisidine)-SnO2 nanocomposites for fabrication of low temperature operative liquefied petroleum gas sensor J. Appl. Phys. 110, 124501 (2011) Additional information on J. Appl. Phys. Well-aligned ZnO nanorods were prepared by the vapor phase transport method on Si covered with a ZnO buffer layer. After the nanostructure growth, Cu was doped into the ZnO nanorods by diffusion at three different temperatures and for different times. Undoped and Cu diffusion-doped ZnO samples are highly textured, with the c axis of the wurtzite structure along the growth direction. The incorporation of Cu caused some slight changes in the nanorod alignment, although the wurtzite crystal structure was maintained. X-ray photoelectron spectroscopy measurements revealed that Cu ions were in a divalent state and substituted for the Zn 2þ ions of the ZnO matrix. Photoluminescence results at 10 K indicate that the incorporation of copper leads to a relative increase of Cu-related structured green band deep level intensity. Magnetic measurements revealed that both undoped and Cu diffusion-doped ZnO samples exhibited room temperature ferromagnetism. It was also found that bound magnetic polarons play an important role in the appearance of room temperature ferromagnetism in Cu diffusion-doped ZnO nanorods.

show abstract

Role of point defects in room-temperature ferromagnetism of Cr-doped ZnO

Cited by 158 publications

References 25 publications

Structural, optical and magnetic properties of Ni-doped ZnO micro-rods grown by the spray pyrolysis method

Structural, optical and magnetic properties of Ni-doped ZnO micro-rods grown by the spray pyrolysis method

Size-dependent antimicrobial properties of CuO nanoparticles against Gram-positive and -negative bacterial strains

Effects of Cu diffusion-doping on structural, optical, and magnetic properties of ZnO nanorod arrays grown by vapor phase transport method

Contact Info

Product

Resources

About