Ferromagnetism induced by planar nanoscale CuO inclusions in Cu-doped ZnO thin films

Sudakar, C.; Thakur, J. S.; Lawes, G.; Naik, R.; Naik, V. M.

doi:10.1103/physrevb.75.054423

Cited by 122 publications

(83 citation statements)

References 24 publications

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“…A similar result was also found by Sharma et al [35]. Sudakar et al [36] reported that Cu-doped ZnO films with concentration lower than 1 at% exhibited ferromagnetic behavior with large saturation magnetization, however, for higher doping concentrations, the saturation magnetization decreased drastically. They proposed that the origin of ferromagnetism in Cu-doped ZnO was the formation of planar CuO nanophase, while Wei et al [37] reported that there was no sign of ferromagnetism down to 10 K in pure Cu 2 O samples.…”

Section: Resultssupporting

confidence: 75%

Co-Precipitation Synthesis and Characterization of Nanocrystalline Zinc Oxide Particles Doped with Cu<sup>2+</sup> Ions

Mukhtar¹,

Munisa²,

Saleh³

2012

MSA

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Nanocrystalline Cu-doped ZnO particles were synthesized by the co-precipitation method. The composition, structural, optical and magnetic characterizations were performed by energy dispersive X-Ray spectroscopy, X-Ray diffraction, UV-Visible spectrometer, and vibrating sample magnetometer. The results confirmed that nanocrystalline Cu-doped ZnO particles have a hexagonal wurtzite structure with a high degree of crystallization and a crystallite size of 10 -16 nm. For Cu above 11 at%, the X-Ray diffraction pattern possessed CuO secondary phase which shows the solubility limit of Cu in the ZnO lattice. Up to 11% at Cu, the presence of Cu in the ZnO lattice as Zn substitution indicated by an in-crease in lattice parameter values. Nanoparticles showed weak ferromagnetic characteristics at room temperature. The absence of secondary phase related to magnetic precipitate shown intrinsic ferromagnetic behaviour.

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Section: Resultssupporting

confidence: 75%

Co-Precipitation Synthesis and Characterization of Nanocrystalline Zinc Oxide Particles Doped with Cu<sup>2+</sup> Ions

Mukhtar¹,

Munisa²,

Saleh³

2012

MSA

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“…However, the inconsistent experimental results raise a new problem of explaining the mechanism of ferromagnetism in TM-doped ZnO. Moreover, it is difficult to exclude the possibility that the ferromagnetism might be brought by a secondary phase of TM oxides or TM dopant clusters [13,14,15]. Consequently, many researchers turned their attention to non-TM doped ZnO and tried to provide undisputed intrinsic DMS.…”

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confidence: 99%

Intrinsic room temperature ferromagnetism in boron-doped ZnO

Yang

et al. 2010

Applied Physics Letters

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We report room temperature ferromagnetism in boron-doped ZnO both experimentally and theoretically. The single phase Zn 1-x B x O films deposited under high oxygen pressure by pulsed-laser deposition show ferromagnetic behavior at room temperature. The saturation magnetization increases monotonously from 0 to 1.5 emu/cm 3 with the increasing of B componentx from 0 to 6.8%. The first-principles calculations based on density functional theory demonstrate that the ferromagnetism in B-doped ZnO originates from the induced magnetic moments of oxygen atoms in the nearest neighbor sites to the B-Zn vacancy pair. The calculated total magnetic moment increasing tendency with B component is well consistent with experiments. * To whom correspondence should be addressed. Email: yjiang@ustb.edu.cn 1 Dilute magnetic semiconductors (DMS) are promising candidates for spintronics devices due to their peculiar magnetic and semiconductor properties. In recent years, researchers have made great efforts to design and fabricate DMS, especially those with Curie temperature (T C ) above room temperature. Among all DMS candidates, ZnO has attracted wide interest, since it is predicted to be an ideal room-temperature DMS by Dietl et al. [1]. The magnetic moments of oxygen atoms around Zn vacancy are confirmed to be an origin of the ferromagnetic (FM) property in pure ZnO system [ 2 , 3 ]. However, the density of Zn vacancy is sensitive to experimental conditions and difficult to be controlled. Transition metal (TM) doping is a traditional method to obtain room temperature ferromagnetism in ZnO system [4,5,6,7,8,9,10,11,12]. However, the inconsistent experimental results raise a new problem of explaining the mechanism of ferromagnetism in TM-doped ZnO. Moreover, it is difficult to exclude the possibility that the ferromagnetism might be brought by a secondary phase of TM oxides or TM dopant clusters [13,14,15]. Consequently, many researchers turned their attention to non-TM doped ZnO and tried to provide undisputed intrinsic DMS. Pan et al. [16] theoretically predicted and experimentally realized room temperature ferromagnetism in carbon-doped ZnO films. A further work by Peng et al. [17] demonstrated the hole-induced mechanism in p-group element-doped FM ZnO system, which opens a new way for studying non-TM doped ZnO DMS.In this letter, we report our experimental study on 2p-group element B-doped ZnO system. First-principles calculations based on the density functional theory justify the intrinsic ferromagnetism in the system is induced by oxygen atoms in the nearest neighbor sites to the B-Zn vacancy pair, which is quite different from the origin of the ferromagnetism in carbon-doped ZnO.All the B-doped ZnO thin films were grown by pulsed-laser deposition (PLD) using a KrF 2 excimer laser operating at 300 mJ/pluse and 10 Hz. The targets were prepared by sintering mixed ZnO (99.99%) The most possible site for B should be tetrahedral or octahedral interstice in ZnO, due to the small radius of B. According to our calculation,...

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“…%. Additionally, Sudakar et al 22 found that ZnO films with Cu concentration of x < 1 at. % grown by reactive magnetron co-sputtering method on c-cut Al 2 O 3 substrates exhibited very clear ferromagnetic behavior with a large M s value of 1.6 l B /Cu, however, for the samples with x > 1 at.…”

Section: Resultsmentioning

confidence: 99%

“…[18][19][20] These theoretical predictions were later supported by experimental observations of room temperature ferromagnetism in Cu-doped ZnO thin films. [21][22][23] However, there are few reports on one-dimensional Cu-doped ZnO nanostructures, especially well-aligned nanorod arrays. 15,24 There are various methods to fabricate one-dimensional transition metal-doped ZnO materials.…”

Section: Introductionmentioning

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

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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.

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Ferromagnetism induced by planar nanoscale CuO inclusions in Cu-doped ZnO thin films

Cited by 122 publications

References 24 publications

Co-Precipitation Synthesis and Characterization of Nanocrystalline Zinc Oxide Particles Doped with Cu<sup>2+</sup> Ions

Co-Precipitation Synthesis and Characterization of Nanocrystalline Zinc Oxide Particles Doped with Cu<sup>2+</sup> Ions

Intrinsic room temperature ferromagnetism in boron-doped ZnO

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

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Ferromagnetism induced by planar nanoscale CuO inclusions in Cu-doped ZnO thin films

Cited by 122 publications

References 24 publications

Co-Precipitation Synthesis and Characterization of Nanocrystalline Zinc Oxide Particles Doped with Cu&lt;sup&gt;2+&lt;/sup&gt; Ions

Co-Precipitation Synthesis and Characterization of Nanocrystalline Zinc Oxide Particles Doped with Cu&lt;sup&gt;2+&lt;/sup&gt; Ions

Intrinsic room temperature ferromagnetism in boron-doped ZnO

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

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Product

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Co-Precipitation Synthesis and Characterization of Nanocrystalline Zinc Oxide Particles Doped with Cu<sup>2+</sup> Ions

Co-Precipitation Synthesis and Characterization of Nanocrystalline Zinc Oxide Particles Doped with Cu<sup>2+</sup> Ions