Abstract Comprehensive understandings for the resistivity−temperature behavior of high-entropy alloy (HEA) films is crucial for assessing their potential as thin-film resistive materials. But due to the great difference between the structure of bulk and film materials, the resistivity−temperature behavior of the bulk HEAs cannot be directly introduced to understand the evolution law of the resistivity of HEA films with temperature. The present work investigated the resistivity change with temperature from room temperature to 1078 K of AlxCoCrFeNi (x = 0.7, 1.0) HEA films composed of face- and body-centered-cubic phases, and compared it with that of bulk HEAs with similar compositions. It was found that the AlxCoCrFeNi HEA films exhibit the ultralow temperature coefficient of resistance (TCR) within a range of ±10 ppm/K, and their resistivity is tunable over a wide range from 191.8 μΩ∙cm (x = 1.0) to 535.9 μΩ∙cm (x = 0.7), which is beyond the reach of conventional alloy films. For both the film and bulk AlxCoCrFeNi HEAs, the resistivity−temperature behaviors exhibit similar characteristics of high resistivity and low TCRs before phase transitions, and can be described by the equation, ρ = b0 + b1T(1 − b2T2), with the consideration of the phonon scattering and the s-d scattering effect in transition metals. The multi-principal element mixing feature of HEAs will open up more approaches to optimize the properties of thin-film resistive materials.

中文翻译：

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Al CoCrFeNi 高熵合金薄膜的电阻率-温度行为

摘要 全面了解高熵合金 (HEA) 薄膜的电阻率-温度行为对于评估其作为薄膜电阻材料的潜力至关重要。但由于体材料和薄膜材料的结构差异很大，不能直接引入体HEA的电阻率-温度行为来理解HEA薄膜的电阻率随温度的演变规律。目前的工作研究了由面心立方相和体心立方相组成的 AlxCoCrFeNi (x = 0.7, 1.0) HEA 薄膜的电阻率随温度从室温到 1078 K 的变化，并将其与具有相似成分的块状 HEA 的电阻率进行了比较。结果表明，AlxCoCrFeNi HEA 薄膜在 ±10 ppm/K 范围内表现出超低的电阻温度系数 (TCR)，并且它们的电阻率可在 191.8 μΩ∙cm (x = 1.0) 到 535.9 μΩ∙cm (x = 0.7) 的宽范围内调节，这是传统合金薄膜无法企及的。对于薄膜和块状 AlxCoCrFeNi HEAs，电阻率 - 温度行为在相变之前表现出类似的高电阻率和低 TCR 特性，并且可以用等式 ρ = b0 + b1T(1 − b2T2) 来描述，考虑到过渡金属中的声子散射和 sd 散射效应。HEA 的多主元混合特性将为优化薄膜电阻材料的性能开辟更多途径。电阻率-温度行为在相变之前表现出类似的高电阻率和低 TCR 的特性，并且可以用方程 ρ = b0 + b1T(1 − b2T2) 描述，同时考虑声子散射和 sd 散射效应过渡金属。HEA 的多主元混合特性将为优化薄膜电阻材料的性能开辟更多途径。电阻率-温度行为在相变之前表现出类似的高电阻率和低 TCR 的特性，并且可以用方程 ρ = b0 + b1T(1 − b2T2) 描述，同时考虑声子散射和 sd 散射效应过渡金属。HEA 的多主元混合特性将为优化薄膜电阻材料的性能开辟更多途径。