Room temperature ferromagnetism of amorphous MgO films prepared by pulsed laser deposition
Amorphous MgO thin films were prepared by pulsed laser deposition (PLD) under various oxygen pressures. The structural, magnetic, and optical properties of the films were investigated. All as-deposited samples exhibit room temperature ferromagnetism, which depend strongly on oxygen pressure. It is found that the saturation magnetization (Ms) initially increases with the oxygen pressure, the maximum Ms of 8.57 emu/cm3 is obtained for the MgO film deposited under an oxygen pressure of 2 mTorr. However, the Ms significantly reduces at higher oxygen pressures. Further X-ray photoelectron spectroscopy and photoluminescence demonstrate that the long-range magnetic order in amorphous MgO films can be attributed to the nonstoichiometry effect and the presence of Mg vacancies.
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