Study of electronic and magnetic properties of vacuum annealed Cr doped ZnO

Singhal, Asmita

doi:10.1016/j.jallcom.2011.11.103

Cited by 20 publications

(11 citation statements)

References 38 publications

(59 reference statements)

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“…A similar annealing effect was reported in the XPS spectra of Mn-doped ZnO 37,38 and Cr-doped ZnO. 39 Hydrogen contamination, which is reflected in the O−H bonds, is reported to induce RT-FM in ZnO films. 25 Our results indicated a reduction in the O c intensity under annealing but with no systematic variations.…”

Section: Resultssupporting

confidence: 69%

“…36 Postannealing in vacuum induced RT-FM in Cr-doped ZnO nanoparticles, which disappeared after annealing in air. 39 For Fe-doped ZnO nanoparticles, annealing in air reduced the M S , annealing in vacuum increased it, and annealing in hydrogen significantly increased both M S and the Curie temperature. 66 A remarkable improvement in the RT-FM of the Co−Fe-doped ZnO films, prepared by magnetron sputtering, was also found after postannealing under vacuum.…”

Section: Resultsmentioning

confidence: 96%

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Influence of Oxygen Defects and Their Evolution on the Ferromagnetic Ordering and Band Gap of Mn-Doped ZnO Films

2020

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We performed a comprehensive investigation on the influence of oxygen vacancies (VO) defects and their evolution under Mn substitution and thermal annealing in different atmospheres on the ferromagnetic ordering and optical energy band gap (E g) of Mn-doped ZnO thin films. All doped films showed a ferromagnetic phase at room temperature, which became stronger at low temperatures. Our results clearly showed a direct link between the concentration of VO and the observed ferromagnetism (FM). By increasing the Mn concentration (C Mn), both photoluminescence and X-ray photoelectron spectroscopy results revealed an enhancement in the concentration of VO, in parallel with a clear improvement in the FM. In addition, the FM in the doped films became stronger after annealing in vacuum and weaker after annealing in air, in accordance with a considerable increase and decrease in the concentration of VO that mediates the observed ferromagnetic order. The results also indicated a direct correlation between the E g behavior and the concentration of VO. Films with a high C Mn having a narrower E g and higher VO level are found to show stronger FM. On increasing the C Mn, a slight shift in the E g to lower values is detected, indicating weak sp–d hybridization. All doped films showed a single phase with würtzite structure, and the Mn2+ ions are proved to substitute for the Zn2+ in the würtzite lattice.

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Section: Resultssupporting

confidence: 69%

Section: Resultsmentioning

confidence: 96%

Influence of Oxygen Defects and Their Evolution on the Ferromagnetic Ordering and Band Gap of Mn-Doped ZnO Films

2020

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“…The energy difference of these two peaks is 23.1 eV, agrees well with the standard value of 22.97 eV which reveals the presence of Zn 2? bound to be oxygen in the ZnO matrix [37,38].…”

Section: Xps Analysismentioning

confidence: 99%

Structural, optical and antibacterial activity studies of neodymium doped ZnO nanoparticles

Vijayaprasath

Murugan

Palanisamy

et al. 2015

J Mater Sci: Mater Electron

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Trivalent neodymium doped ZnO (Zn 1-x Nd x O, x = 0.0, 0.03, 0.06 and 0.09) nanoparticles (NPs) synthesized by co-precipitation method with improved optical and antibacterial performance is reported. X-ray diffraction pattern indicates most of Nd 3? ions are incorporated in Zn 2? ions of ZnO lattice and hence there is no secondary peak of NdO 3 in synthesized ZnO NPs. Fourier transform infrared spectroscopy analysis of synthesized NPs exhibits similar patterns in Zn/Nd-O bands observed at 480 cm -1 . High resolution scanning electron microscopy images revealed the formation of spindle like morphology and the incorporation of Nd ions is confirmed by energy dispersive spectra analysis. UV-visible absorption spectra of pure and Nd doped ZnO NPs showed the variation of the band gap in the range of 3.06-2.65 eV. Raman analysis confirmed the formation of wurtzite structure of NPs was distorted due to Nd substitution in ZnO matrix. X-ray photoelectron spectroscopy confirmed the Nd incorporation in the ZnO lattice as Nd 3? . The prepared Nd doped ZnO NPs showed potential application in antibacterial activities.

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“…However, compared with the widely studied Co‐ and Mn‐doped ZnO systems , both theoretical and experimental studies on Cr‐doped ZnO are scarce. Moreover, the experimental results on the studies of Cr‐doped ZnO are in conflict with each other .…”

Section: Introductionmentioning

confidence: 97%

Effects of Cr-doping concentration on the structural, optical, and magnetic properties of ZnO thin films

Han

Liu

et al. 2013

Phys. Status Solidi A

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Cr-doped ZnO thin films have been prepared on silicon (100) substrates by a radio-frequency (RF) magnetron sputtering method. The crystallographic structures, optical, and magnetic properties of the thin films are investigated by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL), and physical properties measurement system (PPMS), respectively. The XPS results confirm that the chemical-bonding state of the doped Cr ions is þ3. XRD analyses reveal that the Cr ions successfully replace Zn atoms and incorporate into the crystal-lattice positions of ZnO.Magnetic measurements reveal that all the samples have ferromagnetic features and saturation magnetization increases on increasing the dopant concentration. Room-temperature PL spectra show an ultraviolet (UV) emission at 380 nm and a green emission at 500 nm, whose intensity is greatly increased with increased Cr dopant. Moreover, the results of PL further testify that ferromagnetism (FM) is an intrinsic property of the Cr-doped ZnO films and FM can be described by bound magnetic polaron (BMP) models with respect to defect-bound carriers.

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Study of electronic and magnetic properties of vacuum annealed Cr doped ZnO

Cited by 20 publications

References 38 publications

Influence of Oxygen Defects and Their Evolution on the Ferromagnetic Ordering and Band Gap of Mn-Doped ZnO Films

Influence of Oxygen Defects and Their Evolution on the Ferromagnetic Ordering and Band Gap of Mn-Doped ZnO Films

Structural, optical and antibacterial activity studies of neodymium doped ZnO nanoparticles

Effects of Cr-doping concentration on the structural, optical, and magnetic properties of ZnO thin films

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