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We have studied the structural, magnetic and electronic properties of Co-implanted ZnO (0001) films grown on Al2O3 (1120) substrates for different implantation doses and over a wide temperature range. Strong room temperature ferromagnetism…

The prediction of ferromagnetism at room temperature in Co-ZnO thin films has generated a large interest in the community due to the possible applications. However, the results are controversial, going from ferromagnetism to…

Materials Science · Physics 2009-11-11 A. Fouchet , W. Prellier , B. Mercey

We report on the structural and magnetic properties of a cobalt-implanted ZnO film grown on a sapphire substrate. X-ray diffraction and transmission electron microscopy reveal the presence of a (10-10)-oriented hexagonal Co phase in the…

Films of ZnO doped with magnetic ions, Mn and Co and, in some cases, with Al have been fabricated with a very wide range of carrier densities. Ferromagnetic behaviour is observed in both insulating and metallic films, but not when the…

Materials Science · Physics 2009-11-13 A. J. Behan , A. Mokhtari , H. J. Blythe , D. Score , X-H. Xu , J. R. Neal , A. M. Fox , G. A. Gehring

The nature of the often reported room temperature ferromagnetism in transition metal doped oxides is still a matter of huge debate. Herein we report on room temperature ferromagnetism in high quality Co-doped ZnO (Zn1-xCoxO) bulk samples…

The possibility that the apparent room temperature ferromagnetism, often measured in Co-doped ZnO, is due to uncompensated spins at the surface of wurtzite CoO nanoclusters is investigated by means of a combination of density functional…

Mesoscale and Nanoscale Physics · Physics 2015-05-14 Ruairi Hanafin , Thomas Archer , Stefano Sanvito

We report magnetism in carbon doped ZnO. Our first-principles calculations based on density functional theory predicted that carbon substitution for oxygen in ZnO results in a magnetic moment of 1.78 $\mu_B$ per carbon. The theoretical…

Materials Science · Physics 2013-05-29 H. Pan , J. B. Yi , J. Y. Lin , Y. P. Feng , J. Ding , L. H. Van , J. H. Yin

In recent years there has been an intense search for room temperature ferromagnetism in doped dilute semiconductors, which have many potentially applications in spintronics and optoelectronics. We report here the unexpected observation of…

We synthesized pure and Co-doped (6.25 12.5 at.) ZrO$_2$ nanopowders in order to study their magnetic properties.We analyzed magnetic behavior as a function of the amount of Co and the oxygenation, which was controlled by low pressure…

Room-temperature ferromagnetism is observed in (110) oriented ZnO films containing 5 at % of Sc, Ti, V, Fe, Co or Ni, but not Cr, Mn or Cu ions. There are large moments, 1.9 and 0.5 muB/atom for Co- and Ti-substituted oxides, respectively.…

Materials Science · Physics 2009-11-10 M. Venkatesan , C. B. Fitzgerald , J. G. Lunney , J. M. D. Coey

Cobalt and silver co-doping has been undertaken in ZnO thin films grown by pulsed laser deposition in order to investigate the ferromagnetic properties in ZnO-based diluted magnetic materials and to understand the eventual relation between…

The realization of semiconductors that are ferromagnetic above room temperature will potentially lead to a new generation of spintronic devices with revolutionary electrical and optical properties. Transition temperatures in doped ZnO are…

Strongly Correlated Electrons · Physics 2009-11-11 XH Xu , AJ Behan , M Ziese , HJ Blythe , JR Neal , A Mokhtari , MR Ibrahim , AM Fox , GA Gehring

Colloidal cobalt-doped TiO2 (anatase) nanocrystals were synthesized and studied by electronic absorption, magnetic circular dichroism, transmission electron microscopy, magnetic susceptibility, cobalt K-shell X-ray absorption spectroscopy,…

Materials Science · Physics 2007-05-23 J. Daniel Bryan , Steve M. Heald , Scott A. Chambers , Daniel R. Gamelin

Magnetic 3d-ions doped into wide-gap oxides show signatures of room temperature ferromagnetism, although their concentration is two orders of magnitude smaller than that in conventional magnets. The prototype of these exceptional materials…

Materials Science · Physics 2009-11-13 C. D. Pemmaraju , R. Hanafin , T. Archer , H. B. Braun , S. Sanvito

Clear evidence of ferromagnetic behavior at temperatures >400 K as well as spin polarization of the charge carriers have been observed in ZnMnO thin films grown on Al2O3 and MgO substrates. The magnetic properties depended on the exact Mn…

The observed correlation of oxygen vacancies and room temperature ferromagnetic ordering in Co doped ZnO1-o nanoparticles reported earlier (Naeem et al Nanotechnology 17, 2675-2680) has been further explored by transport and optical…

Materials Science · Physics 2007-12-10 M. Naeem , S. K. Hasanain , A. Mumtaz

The origin of room temperature (RT) ferromagneticlike behavior in ZnO-based diluted magnetic semiconductors is still an unclear topic. The present work concentrates on the appearance of RT magnetic moments in just mixed ZnO/Co3O4 mixtures…

We report room temperature ferromagnetism in boron-doped ZnO both experimentally and theoretically. The single phase Zn1-xBxO films deposited under high oxygen pressure by pulsed-laser deposition show ferromagnetic behavior at room…

Materials Science · Physics 2015-05-18 X. G. Xu , H. L. Yang , Y. Wu , D. L. Zhang , S. Z. Wu , J. Miao , Y. Jiang

Ab initio studies have theoretically predicted room temperature ferromagnetism in crystalline SnO2, ZrO2 and TiO2 doped with non magnetic element from the 1A column as K and Na. Our purpose is to address experimentally the possibility of…

Materials Science · Physics 2011-01-25 S. K. Srivastava , P. Lejay , B. Barbara , S. Pailhès , V. Madigou , G. Bouzerar

Using the spectroscopies based upon x-ray absorption, we have studied the structural and magnetic properties of Zn$_{1-x}$Co$_{x}$O films ($x$ = 0.1 and 0.25) produced by reactive magnetron sputtering. These films show ferromagnetism with a…

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