Absence of ferromagnetism in Co-doped ZnO prepared by thermal diffusion of Co atoms

Zhang, Z.; Chen, Q.; Lee, H. D.; Xue, Yawen; Sun, Yan–Hui; Chen, H.; Chen, F.; Chu, Wei‐Kan

doi:10.1063/1.2244480

Cited by 36 publications

(8 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[6] However, many recent studies have shown that Mn 2 + -and Co 2 + -doped ZnO and similar materials are not ferromagnetic. [7][8][9][10][11] Furthermore, room-temperature ferromagnetism has been found to be a universal characteristic of nanoparticles of inorganic material which are otherwise non-magnetic. [12,13] Thus, the ferromagnetism of transition-metal-ion-doped oxides reported in the literature could arise from the nanoparticulate nature of the oxide host.…”

Section: Introductionmentioning

confidence: 99%

On the Defect Origin of the Room‐Temperature Magnetism Universally Exhibited by Metal‐Oxide Nanoparticles

et al. 2010

View full text Add to dashboard Cite

The occurrence of ferromagnetism in nanoparticles of otherwise non-magnetic oxides seems to be well established. It is, however, necessary to understand the origin of ferromagnetism in these materials. Herein, we present a combined study of the magnetic properties and photoluminescence (PL) behavior of nanoparticles of ZnO, ZrO(2), and MgO annealed at different temperatures (and therefore of different sizes). We find that the magnetization and the intensity of the bands due to defects vary parallel in all these materials. The adsorption of ethanol leads to a decrease in the magnetization and to a reduced intensity of the defect PL band of ZnO nanoparticles whereas UV irradiation has the opposite effect. We have also examined the effect of the morphology of the ZnO on the properties.

show abstract

Section: Introductionmentioning

confidence: 99%

On the Defect Origin of the Room‐Temperature Magnetism Universally Exhibited by Metal‐Oxide Nanoparticles

et al. 2010

View full text Add to dashboard Cite

show abstract

“…Though these XRD results indicate the absence of secondary phase or Fe metal clusters, a direct identification of local clusters may rely on the high-resolution transmission electron microscopy or Raman spectroscopy. 13 The paired TM ions ͑mediated by one oxygen ion͒ are expected to have superexchange interaction with each other thus gives rise to an antiferromagnetic behavior. Figure 2 shows the M-H curves of Fe: CeO 2 with different Fe content.…”

Section: Resultsmentioning

confidence: 99%

Effects of Fe doping and the dielectric constant on the room temperature ferromagnetism of polycrystalline CeO2 oxides

Wen

Zhang

Yang

et al. 2010

Journal of Applied Physics

View full text Add to dashboard Cite

Impact of sintering temperature on the physical properties of the superconducting ferromagnet: Ru Sr 2 Eu 1.5 Ce 0.5 Cu 2 O 10 Ce 1−x Fe x O 2−␦ polycrystalline samples with x = 0% -8% were synthesized by the solid phase reaction method at a low sintering temperature of 1250°C, and the effect of Fe content on the magnetic behaviors has been systemically investigated. It is found that the pure CeO 2 samples are diamagnetic, while doped samples unambiguously show the existence of room temperature ͑RT͒ ferromagnetism ͑FM͒. With the increase in x, the saturation magnetization ͑M s ͒ exhibits a steep increase to a maximum M s of 1 emu/g at x = 2.7% and then drop exponentially. A small amount of Fe doping ͑0.9%͒ promotes the densification and induces a large dielectric constant ͑͒. Our result shows that a relatively large and a proper Fe concentration are critical to establish the magnetic polaron and provide strong RT FM in CeO 2 .

show abstract

“…the saturation moment and Curie temperature for Mn doped ZnO ranges from 0.075 μ B /Mn, 400 K [11] to 0.17 μ B /Mn, 30 -45 K [17], respectively. In contrast to these publications, other groups reported the observation of antiferromagnetism [18][19][20], spinglass behavior [21,22], and paramagnetism [19,[23][24][25] in TM-doped ZnO. Recently it was also found that nanoscale precipitates can contribute to the ferromagnetic properties substantially.…”

Section: Introductionmentioning

confidence: 90%

Ferromagnetic transition metal implanted ZnO: A diluted magnetic semiconductor?

Zhou

Potzger

et al. 2009

Vacuum

View full text Add to dashboard Cite

Recently theoretical works predict that some semiconductors (e.g. ZnO) doped with magnetic ions are diluted magnetic semiconductors (DMS). In DMS magnetic ions substitute cation sites of the host semiconductor and are coupled by free carriers resulting in ferromagnetism. One of the main obstacles in creating DMS materials is the formation of secondary phases because of the solid-solubility limit of magnetic ions in semiconductor host. In our study transition metal ions were implanted into ZnO single crystals with the peak concentrations of 0.5-10 at.%. We established a correlation between structural and magnetic properties. By synchrotron radiation X-ray diffraction (XRD) secondary phases

show abstract

Absence of ferromagnetism in Co-doped ZnO prepared by thermal diffusion of Co atoms

Cited by 36 publications

References 32 publications

On the Defect Origin of the Room‐Temperature Magnetism Universally Exhibited by Metal‐Oxide Nanoparticles

On the Defect Origin of the Room‐Temperature Magnetism Universally Exhibited by Metal‐Oxide Nanoparticles

Effects of Fe doping and the dielectric constant on the room temperature ferromagnetism of polycrystalline CeO2 oxides

Ferromagnetic transition metal implanted ZnO: A diluted magnetic semiconductor?

Contact Info

Product

Resources

About