Room temperature ferromagnetism in Co-doped CuAlO₂ nanofibers fabricated by electrospinning

Abstract

One-dimensional, diluted magnetic semiconductor nanofibers have attracted increasing attention for their unique magnetic properties, large specific surface area, and high porosity. These qualities lead to excellent performance in magneto-optical devices, magnetic resonance imaging, ferrofluids and magnetic separation. The purpose of this study is to fabricate P-type one dimensional CuAlO₂-based diluted magnetic semiconductor nanofibers. First, we fabricated CuAl_0.95Co_0.05O₂ nanofibers with an average diameter of 1 μm with the electrospinning method. The annealed nanofibers were thermally treated at a temperature of 1 100 °C and then shrunk to a diameter of about 650 nm. We used X-ray diffraction measurements and Raman spectra to confirm that the CuAl_0.95Co_0.05O₂ nanofibers had a single impurity free delafossite phase. The X-ray photoelectron spectroscopy analysis indicates that Co was present in the +2 oxidation state, resulting in an room temperature ferromagnetism in the CuAl_0.95Co_0.05O₂ fiber. This contrasts with nonmagnetism in pristine CuAlO₂ fiber. The coercivity (H _c) value of 65.26 Oe and approximate saturation magnetization (M _s) of 0.012 emu/g demonstrate good evidence of ferromagnetism at room temperature for CuAl_0.95Co_0.05O₂ nanofibers.

Keywords

DMS / Co-doped CuAlO₂ / nanofibers / electrospinning / ferromagnetism

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