This article demonstrates the effect of magnetic field-assisted annealing on the magnetic and structural properties of the sol–gel-derived copper oxide films grown on n-Si substrates. The samples were annealed at 450 °C with and without the presence of an external magnetic field. The comparison of XRD and FESEM results of the annealed samples under three different magnetic fields of 280, 400, and 520 G show that the particle sizes of the CuO films were increased with the increase in magnetic field during thermal annealing. The presence of magnetic field during annealing also modulates reflectance characteristics of the film which can be explored for various optoelectronic applications. Most interestingly, CuO films exhibit ferromagnetic characteristics which can be modulated by varying the externally applied magnetic field during the annealing of the samples. The obtained retentivity and coercivity values of annealed samples in the presence of magnetic field vertically downward are $1.84 \times 10^{-2}$ emu/gm and 280.60 Oe, respectively. These are significantly higher than the values of thermally annealed samples.

中文翻译：

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通过磁场辅助退火调制氧化铜薄膜中的室温铁磁性

本文展示了磁场辅助退火对生长在 n-Si 衬底上的溶胶-凝胶衍生的氧化铜薄膜的磁性和结构特性的影响。样品在有和没有外部磁场的情况下在 450 °C 下退火。退火样品在 280、400 和 520 G 三种不同磁场下的 XRD 和 FESEM 结果的比较表明，CuO 薄膜的粒径随着热退火过程中磁场的增加而增加。退火过程中磁场的存在也会调节薄膜的反射特性，这可以用于各种光电应用。最有趣的是，CuO 薄膜表现出铁磁特性，可以通过在样品退火过程中改变外部施加的磁场来进行调制。在存在垂直向下磁场的情况下，退火样品的保持率和矫顽力值分别为 $1.84 \times 10^{-2}$ emu/gm 和 280.60 Oe。这些值明显高于热退火样品的值。