Publication Details

Cao, Q., Zhu, D., Fu, M., Cai, L., Yang, P., Li, S., Zhu, Y., Ma, X., Liu, G., Chen, Y., Yan, S., Mei, L. & Wang, X. (2016). Robust ferromagnetism of single crystalline CoxZn1−xO (0.3 ≤ x ≤ 0.45) epitaxial films with high Co concentration. Applied Physics Letters, 109 (5), 052404-1-052404-5.


In contrast to conventional dilute magnetic semiconductors with concentrations of magnetic ions of just a few percent, here, we report the fabrication of epitaxial Cox Zn 1− xO single crystalline films with Co concentrations from x = 0.3 up to 0.45 by radio-frequency oxygen-plasma-assisted molecular beam epitaxy. The films retain their single crystalline wurtzite structure without any other crystallographic phase from precipitates, based on reflection high energy electron diffraction, X-ray diffraction, transmission electron microscopy, and Raman scattering. The results of X-ray diffraction, optical transmission spectroscopy, and in-situ X-ray photoelectron spectroscopy confirm the incorporation of Co2+ cations into the wurtzite lattice. The films exhibit robust ferromagnetism and the magneto-optical Kerr effect at room temperature. The saturation magnetization reaches 265 emu/cm3 at x = 0.45, which corresponds to the average magnetic moment of 1.5 μB per Co atom.



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