Dose dependence of ferromagnetism in Co-implanted ZnO

作者：Akdogan Numan^*; Zabel Hartmut; Nefedov Alexei; Westerholt Kurt; Becker Hans Werner; Goek Safak; Khaibullin Rustam; Tagirov Lenar

来源：Journal of Applied Physics, 2009, 105(4): 043907.

DOI：10.1063/1.3082080

• cobalt
• ferromagnetic materials
• Hall effect
• II-VI semiconductors
• ion implantation
• magnetic circular dichroism
• magnetic thin films
• magnetisation
• semiconductor thin films
• semimagnetic semiconductors
• superparamagnetism
• wide band gap semiconductors
• X-ray scattering
• zinc compounds

We have studied the structural, magnetic, and electronic properties of Co-implanted ZnO(0001) films grown on Al(2)O(3) (1120) substrates for different implantation doses and over a wide temperature range. Strong room temperature ferromagnetism is observed with magnetic parameters depending on the cobalt implantation dose. A detailed analysis of the structural and magnetic properties indicates that there are two magnetic phases in Co-implanted ZnO films. One is a ferromagnetic phase due to the formation of long range ferromagnetic ordering between implanted magnetic cobalt ions in the ZnO layer and the second one is a superparamagnetic phase, which occurs due to the formation of metallic cobalt clusters in the Al(2)O(3) substrate. Using x-ray resonant magnetic scattering, the element specific magnetization of cobalt, oxygen, and Zn was investigated. Magnetic dichroism was observed at the Co L(2,3) edges as well as at the O K edge. In addition, the anomalous Hall effect is also observed, supporting the intrinsic nature of ferromagnetism in Co-implanted ZnO films.

• 出版日期2009-2-15