Ferromagnetism in 200-MeV Ag+15-ion-irradiated Co-implanted ZnO thin films

Angadi, Basavaraj; Jung, YunJae; Choi, Won Kook; Kumar, Ravi; Jeong, Kyu Shik; Shin, Sangwoo; Lee, J. H.; Song, Joong-Ho; Khan, M. Wasi; Srivastava, J.P.

doi:10.1063/1.2192577

Cited by 47 publications

(21 citation statements)

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“…Recently high energy electronic excitation due to swift heavy ion (SHI) irradiation has been considered as a great tool for the modifications in the structural, optical and magnetic properties of various materials in bulk as well as thin films [21,22]. Formation of single phase Co-implanted ZnO thin films using SHI irradiation has been reported by Angadi et al [23]. It has been shown earlier also that Modifications in the structural and optical properties of 100 MeV Ni 7+ ions irradiated cobalt doped ZnO thin films (Zn 1Àx Co x O, x = 0.05) prepared by sol-gel route were studied.…”

Section: Introductionmentioning

confidence: 98%

Swift heavy ion induced modifications in cobalt doped ZnO thin films: Structural and optical studies

Kumar

Singh

2009

Applied Surface Science

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Section: Introductionmentioning

confidence: 98%

Swift heavy ion induced modifications in cobalt doped ZnO thin films: Structural and optical studies

Kumar

Singh

2009

Applied Surface Science

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“…These predictions largely boosted intensive experimental activities on transition metal doped GaN and * Electronic address: S.Zhou@fzd.de ZnO. A large number of research groups have reported the experimental observation of ferromagnetism in TM (from Sc to Ni) doped ZnO [7,8,9,10,11,12,13,14,15] fabricated by various methods including ion implantation. For a comprehensive review, see Ref.…”

Section: Introductionmentioning

confidence: 99%

Crystallographically oriented Co and Ni nanocrystals inside ZnO formed by ion implantation and postannealing

et al. 2008

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In the last decade, transition metal doped ZnO has been intensively investigated as a route to room temperature diluted magnetic semiconductors (DMS). However the origin for the reported ferromagnetism in ZnO based DMS remains questionable. Possible options are diluted magnetic semiconductors, spinodal decomposition or secondary phases. In order to clarify this question, we have performed a thorough characterization of the structural and magnetic properties of Co and Ni implanted ZnO single crystals. Our measurements reveal that Co or Ni nanocrystals (NCs) are the major contribution of the measured ferromagnetism. Already in the as-implanted samples, Co or Ni NCs have formed, and they exhibit superparamagnetic properties. The Co or Ni NCs are crystallographically oriented with respect to the ZnO matrix. Their magnetic properties, e.g. the anisotropy and the superparamagnetic blocking temperature can be tuned by annealing. We discuss the magnetic anisotropy of Ni NCs embedded in ZnO concerning the strain anisotropy.

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“…Ion beam gives a better alternative for converting the amorphous Si to crystalline Si by irradiation at temperatures up to a few hundred degree centigrade. Low-energy irradiation upto a few MeV has been exploited 67 for the recrystallisation process. In this energy region, either the nuclear energy loss dominates or both the electronic and nuclear energy loss are of comparable value.…”

Section: Ion Beam Induced Epitaxial Crystallisationmentioning

confidence: 99%

Modification and Characterisation of Materials by Swift Heavy Ions

Avasthi¹

2009

DSJ

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Swift heavy ions (SHI) available with 15 million Volt Pelletron accelerator at Inter University Accelerator Centre (IUAC) Delhi, formerly known as Nuclear Science Centre, (NSC), provide a unique opportunity to researchers for accelerator based materials science research. The major research areas can be broadly categorised as electronic sputtering, interface modifications, synthesis and modification of nanostructures, phase transitions and ion beam-induced epitaxial crystallisation. In, general, SHI irradiation based-materials may not be economically feasible, still it could be of interest for very specific cases in defence and space research. The paper gives a glimpse of the current research activities in materials science with SHIs, at IUAC.Keywords: Swift heavy ions, SHI, materials science, materials research systhesis of materials, characterisation of materials, nuclear energy loss, ion energy loss, electronic energy-loss-defects in materials, defect engineering INTRODUCTIONThe ions with energy ranging from a fraction of keV to GeV are useful in synthesis, modification and characterization of materials. The energetic ions during their passage through a material loose energy via two processes. These are nuclear energy loss S n and electronic energy loss S e . In the former process, the energy is lost by elastic collisions of incident ions with the atoms in the material, which is dominant at low energies. In the electronic energy loss process, dominant at high energies (>1 MeV/nucleon), the energy is lost by inelastic collisions of the ion with the atoms, leading to excitation or ionisation of the atoms. At these energies of heavy ions, the velocity of the ion is comparable to or higher than the velocity of Bohr electron. The ions with such high energies are also referred to as Swift Heavy Ions (SHI). The electronic energy loss for SHI is, generally, about two orders of magnitude higher than the nuclear energy loss1 . An interesting characteristic of the SHI is that it creates a columnar type of defect along its path (called as ion track), specially, in insulators. SHI during its passage through material can cause defect annealing, cluster of point defects and columnar type of defects depending on the mass and energy of the ion and the material. Therefore the SHI can be used for engineering the defects in the materials. The parameters of ion beam, which play crucial role in defect engineering, are the energy deposited per unit length and the fluence.The ion mass and its energy, decide the magnitudes of the electronic as well as nuclear energy losses. Especially for heavy ions at high energies (i.e., for SHI), the electronic energy loss decides the type of defects as the nuclear energy loss. The other ion beam parameter, fluence, dictates the number of defects (produced). The number of ion

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Ferromagnetism in 200-MeV Ag+15-ion-irradiated Co-implanted ZnO thin films

Cited by 47 publications

References 18 publications

Swift heavy ion induced modifications in cobalt doped ZnO thin films: Structural and optical studies

Swift heavy ion induced modifications in cobalt doped ZnO thin films: Structural and optical studies

Crystallographically oriented Co and Ni nanocrystals inside ZnO formed by ion implantation and postannealing

Modification and Characterisation of Materials by Swift Heavy Ions

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