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Title: Post-annealing effect on the room-temperature ferromagnetism in Cu-doped ZnO thin films

In this work, we investigated the structural and magnetic properties of both as-deposited and post-annealed Cu-doped ZnO thin films for better understanding the possible mechanisms of room-temperature ferromagnetism (RT-FM) in ZnO-based diluted magnetic oxides. All of the films have a c-axis-oriented wurtzite structure and display RT-FM. X-ray photoelectron spectroscopy results showed that the incorporated Cu ions in as-deposited films are in 1+ valence state merely, while an additional 2+ valence state occurs in post-annealed films. The presence of Cu{sup 2+} state in post-annealed film accompanies a higher magnetization value than that of as-deposited film and, in particular, the magnetization curves at 10 K and 300 K of the post-annealed film separate distinctly. Since Cu{sup 1+} ion has a filled 3d band, the RT-FM in as-deposited Cu-doped ZnO thin films may stem solely from intrinsic defects, while that in post-annealed films is enhanced due to the presence of CuO crystallites.
Authors:
; ; ;  [1] ;  [2]
  1. Department of Applied Physics, National University of Kaohsiung, Kaohsiung 811, Taiwan (China)
  2. Institute of Electro-Optical Science and Engineering, National Cheng Kung University, Tainan 701, Taiwan (China)
Publication Date:
OSTI Identifier:
22409987
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 117; Journal Issue: 17; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANNEALING; COPPER IONS; COPPER OXIDES; CUBIC LATTICES; DOPED MATERIALS; FERROMAGNETISM; MAGNETIC PROPERTIES; MAGNETIZATION; TEMPERATURE DEPENDENCE; TEMPERATURE RANGE 0273-0400 K; THIN FILMS; VALENCE; X-RAY PHOTOELECTRON SPECTROSCOPY; ZINC OXIDES