Structural and magnetic properties of Gd-doped ZnO

Bantounas, Ioannis; Singaravelu, Venkatesh; Roqan, Iman S.; Schwingenschlögl, Udo

doi:10.1039/c4tc01237b

Cited by 26 publications

(17 citation statements)

References 30 publications

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“…Therefore, s-d interaction is unlikely to be the reason for the strong FM in GdZnO films. Our previous DFT prediction showed that Gd complex with intrinsic defects does not induce FM in Gd-doped ZnO, 44 which is in line with the results yielded by the XMCD experiments. 15 (ii) The other possibility is defects-induced FM, which requires the defect band and the CBM located near the Fermi level.…”

Section: (A)-4(c) Furthermore M Vs H/t Curves (Figs 4(d)-4(f)supporting

confidence: 76%

Obtaining strong ferromagnetism in diluted Gd-doped ZnO thin films through controlled Gd-defect complexes

Roqan

Singaravelu

Zhang

et al. 2015

Journal of Applied Physics

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Section: (A)-4(c) Furthermore M Vs H/t Curves (Figs 4(d)-4(f)supporting

confidence: 76%

Obtaining strong ferromagnetism in diluted Gd-doped ZnO thin films through controlled Gd-defect complexes

Roqan

Singaravelu

Zhang

et al. 2015

Journal of Applied Physics

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“…Figure 13 shows a 2-Gd complex with V O and Zn i , respectively, suggesting three possibilities of magnetic coupling that lead to the observed RTFM in Gd-doped ZnO deposited at different oxygen-deficiency conditions. First, Gd induces FM through s-f or s-d coupling, which is not possible because the f state is far the CBM and does not overlap with the Fermi level, an observation that is in line with our earlier DFT calculations [51]. Second, defect-induced RTFM can be possible in this case if the defect band and the CBM are located near the Fermi level.…”

Section: The Origin Of the Ferromagnetism In Gd-doped Zno Filmssupporting

confidence: 66%

Magnetic Properties of Gadolinium-Doped ZnO Films and Nanostructures

Roqan¹,

Aravindh²,

Singaravelu³

2016

Magnetic Materials

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The magnetic properties of Gd-doped ZnO films and nanostructures are important to the development of next-generation spintronic devices. Here, we elucidate the significant role played by Gd-oxygen-deficiency defects in mediating/inducing ferromagnetic coupling in in situ Gd-doped ZnO thin films deposited at low oxygen pressure by pulsed laser deposition (PLD). Samples deposited at higher oxygen pressures exhibited diamagnetic responses. Vacuum annealing was used on these diamagnetic samples (grown at a relatively high oxygen pressures) to create oxygendeficiency defects with the aim of demonstrating reproducibility of room-temperature ferromagnetism (RTFM). Samples annealed at oxygen environment exhibited superparamagnetism and blocking-temperature effects. The samples possessed secondary phases; Gd segregation led to superparamagnetism. Theoretical studies showed a shift of the 4f level of Gd to the conduction band minimum (CBM) in Gd-doped ZnO nanowires, which led to an overlap with the Fermi level, resulting in strong exchange coupling and consequently RTFM.

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“…The observed paramagnetic behavior might be due to random distribution of the Gd 3+ ions in ZnO giving rise to formation of some sort of weak interaction depending on composition and distance between the magnetic dopants, thereby influencing the strength of direct or indirect coupling among the magnetic ions. Our observation of paramagnetism in Gd doped ZnO is well supported by the recent theoretical report using density functional theory which predicts "paramagnetic" ground state for wurtzite ZnO lattice at room temperature based on the distance between the magnetic ions [35].…”

Section: Resultssupporting

confidence: 68%

Intense violet–blue emission and paramagnetism of nanocrystalline Gd3+ doped ZnO ceramics

et al. 2015

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Nanocrystalline Zn 1x Gd x O (x = 0, 0.02, 0.04, 0.06, and 0.08) ceramics were synthesized by ball milling and subsequent solid-state reaction. The transmission electron microscopy (TEM) micrograph of as synthesized samples revealed the formation of crystallites with an average diameter of 60 nm, and the selected area electron diffraction (SAED) pattern confirmed the formation of wurtzite structure. A red shift in the band gap was observed with increasing Gd 3+ concentration. The photoluminescence of nanocrystalline Gd 3+ doped ZnO exhibited a strong violet-blue emission. Concentration dependence of the emission intensity of Gd 3+ in ZnO was studied, and the critical concentration was found to be 4 mol% of Gd 3+ . The Gd 3+ doped ZnO exhibited paramagnetic behavior at room temperature, and the magnetic moment increased with Gd 3+ concentration.

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Structural and magnetic properties of Gd-doped ZnO

Cited by 26 publications

References 30 publications

Obtaining strong ferromagnetism in diluted Gd-doped ZnO thin films through controlled Gd-defect complexes

Obtaining strong ferromagnetism in diluted Gd-doped ZnO thin films through controlled Gd-defect complexes

Magnetic Properties of Gadolinium-Doped ZnO Films and Nanostructures

Intense violet–blue emission and paramagnetism of nanocrystalline Gd3+ doped ZnO ceramics

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