2008/01/24 by Shengqiang Zhou, К. Potzger, K. Potzger +7 · 181 citations
Chemistry · Materials Science · Physics and Astronomy · #Annealing (glass) #Chemistry #Condensed matter physics #Copper-based nanomaterials and applications #Doping #Ferromagnetism #Ga2O3 and related materials #Ion #Ion implantation #Magnetic anisotropy #Magnetic field #Magnetic semiconductor #Magnetization #Materials science #Metallurgy #Nanocrystal #Nanotechnology #Optoelectronics #Phase (matter) #Semiconductor #Spinodal decomposition #Superparamagnetism #ZnO doping and properties #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.77.035209
published in Physical Review B 77(3) (American Physical Society) · 13 pages, 14 figures
openalex publication_date 2008/01/24 · arxiv created 2009/08/04 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
In the last decade, transition-metal-doped ZnO has been intensively investigated as a route to room-temperature diluted magnetic semiconductors (DMSs). 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.