Abstract The thermal conductivity of post-perovskite (ppv), the highest-pressure polymorph of MgSiO3 in the Earth's mantle, is one of the most important transport properties for providing better constraints on the temperature profile and dynamics at the core-mantle boundary (CMB). Incorporation of Fe into ppv can affect its conductivity, which has never been experimentally investigated. Here we determined the lattice thermal conductivities of ppv containing 3 mol% and 10 mol% of Fe at high P-T conditions – of pressures up to 149 GPa and 177 GPa, respectively, and temperatures up to 1560 K – by means of the recently developed pulsed light heating thermoreflectance technique combining continuous wave heating lasers. We found that the incorporation of Fe into ppv moderately reduces its lattice thermal conductivity as it increases the Fe content. The bulk conductivity of ppv dominant pyrolite is estimated as 1.5 times higher than that of pyrolite consisting of bridgmanite and ferropericlase in the lower mantle, which agrees with the traditional view that ppv acts as a better heat conductor than bridgmanite in the Earth's lowermost mantle.

中文翻译：

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地球最下地幔中含铁后钙钛矿的热导率

摘要 后钙钛矿 (ppv) 的热导率是地幔中 MgSiO3 的最高压力多晶型物，是最重要的传输特性之一，可以更好地约束核 - 地幔边界 (CMB) 的温度分布和动力学。 ）。将 Fe 掺入 ppv 会影响其电导率，这一点从未被实验研究过。在这里，我们确定了在高 PT 条件（压力分别高达 149 GPa 和 177 GPa，温度高达 1560 K）下，含有 3 mol% 和 10 mol% Fe 的 ppv 的晶格热导率——通过最近开发的脉冲结合连续波加热激光器的光加热热反射技术。我们发现将 Fe 掺入 ppv 会随着 Fe 含量的增加而适度降低其晶格热导率。