Ferromagnetism in polycrystalline Cr-doped ZnO films: Experiment and theory

• Published in: Solid state communications Vol. 146; no. 9; pp. 420 - 424
• Main Authors: Li, Luyan, Liu, Hui, Luo, Xiaoguang, Zhang, Xiao, Wang, Weihua, Cheng, Yahui, Song, Qinggong
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.06.2008; Elsevier
• Subjects: A. Cr-doped ZnO films; A. Diluted magnetic semiconductor; C. Band structure; Condensed matter: electronic structure, electrical, magnetic, and optical properties; D. Room-temperature ferromagnetism; Exact sciences and technology; Magnetic properties and materials; Magnetic semiconductors; Physics; Studies of specific magnetic materials; D. Room-temperature ferromagnetism; 75.50.Pp; A. Diluted magnetic semiconductor; A. Cr-doped ZnO films; C. Band structure; Band structure; Curie point; Doping; Polycrystals; Chromium additions; Hybridization; Semimagnetic semiconductors; Cathode sputtering; Polarized spin; Density functional method; Impurity site; Zinc oxide; Ferromagnetism; 75.50.Pp;A. Diluted magnetic semiconductor;A. Cr-doped ZnO films;D. Room-temperature ferromagnetism;C. Band structure; Saturation magnetization
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/j.ssc.2008.03.024

Room-temperature ferromagnetism is found in polycrystalline Cr x Zn 1− x O ( 0 ≤ x ≤ 0.091 ) films prepared by magnetron sputtering. The saturated magnetization is ∼ 0.58 μ B/Cr with x = 0.012 , and decreases with increased Cr dopant. The Curie temperatures of the samples are above 400 K. First principles calculations based on density functional theory predict that the electrons of Cr-doped ZnO films at Fermi level are 100% spin polarized when two Zn sites are substituted by Cr atoms in the nearest neighbour configuration. The spin polarized carriers and the p–d hybridization between Cr and its four neighbouring O atoms are responsible for observed ferromagnetism.