Dose dependence of ferromagnetism in Co-implanted ZnO

Numan Akdogan; Hartmut Zabel; Alexei Nefedov; Kurt Westerholt; Hans-Werner Becker; Safak Goek; Rustam Khaibullin; Lenar Tagirov

doi:10.1063/1.3082080

arXiv · 0807.4711

Dose dependence of ferromagnetism in Co-implanted ZnO

Numan Akdogan·Hartmut Zabel·Alexei Nefedov·Kurt Westerholt·Hans-Werner Becker·Safak Goek·Rustam Khaibullin·Lenar Tagirov

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Abstract

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 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, the second one is a superparamagnetic phase, which occurs due to the formation of metallic cobalt clusters in the Al2O3 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 L2,3 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.

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Numan Akdogan, Hartmut Zabel, Alexei Nefedov, Kurt Westerholt, Hans-Werner Becker, Safak Goek, Rustam Khaibullin, Lenar Tagirov. 2008-07-29. Dose dependence of ferromagnetism in Co-implanted ZnO. https://doi.org/10.1063/1.3082080

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