NiO nanopowder is produced through plasma-chemical synthesis in a low-pressure arc reactor in an atmosphere of 80% Ar + 20% O2 at a pressure of 40 (sample 1) and 180 Pa (sample 2). The crystalline, morphological, and impedance properties are studied by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and impedance spectroscopy. It is shown that an increase in pressure leads to the synthesis of nanomaterials with fundamentally different crystalline and electrical properties. Sample 1 shows a non-stoichiometric composition (Ni42O58), a face-centered cubic lattice, and a size of coherent scattering regions (CSR) of 16 nm. The impedance studies shows that the frequency dependences are well described by the Debye relaxation model, at low frequencies the real part of the dielectric constant is equal to 35, and thermal studies show a negative temperature coefficient of resistance (NTCR). Sample 2 has an amorphous structure, almost stoichiometric composition (Ni48O52). At low frequencies, the real and imaginary parts of the dielectric constant reaches 105. The anomaly is explained by the formation of a double electric layer near the electrodes due to proton-ion conductivity.

中文翻译：

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淬火速率对NiO纳米颗粒结晶和阻抗特性的影响

NiO 纳米粉末是在低压电弧反应器中，在 80% Ar + 20% O2 的气氛中，在 40（样品 1）和 180 Pa（样品 2）的压力下通过等离子体化学合成生产的。通过 X 射线衍射、扫描电子显微镜、能量色散 X 射线光谱和阻抗光谱研究结晶、形态和阻抗特性。结果表明，压力的增加会导致合成具有根本不同的晶体和电学特性的纳米材料。样品 1 显示非化学计量组成 (Ni42O58)、面心立方晶格和 16 nm 的相干散射区 (CSR) 大小。阻抗研究表明，德拜弛豫模型很好地描述了频率依赖性，在低频下，介电常数的实部等于 35，和热研究表明电阻温度系数为负 (NTCR)。样品 2 具有无定形结构，几乎是化学计量成分 (Ni48O52)。在低频时，介电常数的实部和虚部达到 105。这种异常的原因是由于质子离子传导性在电极附近形成了双电层。