Effect of iron content on electrical conductivity of ferropericlase with implications for the spin transition pressure
Effect of iron content on electrical conductivity of ferropericlase with implications for the spin transition pressure
复制标题
DOI：
10.1029/2010jb007801
复制
发表时间：
2011-04
影响因子：
--
通讯作者：
T. Yoshino;E. Ito;T. Katsura;D. Yamazaki;Shuanming Shan;Xinzhuan Guo;M. Nishi;Y. Higo;K. Funakoshi
中科院分区：
文献类型：
--
作者：
T. Yoshino;E. Ito;T. Katsura;D. Yamazaki;Shuanming Shan;Xinzhuan Guo;M. Nishi;Y. Higo;K. Funakoshi
[1] 通过原位电导率测量，研究了方镁石中铁的压力诱导电子自旋跃迁与方镁石中铁含量的函数关系。使用配备烧结金刚石砧的 Kawai 型多砧装置，测量方镁石 (Mg1-x,Fex)O (x = 0.07、0.10、0.13、0.17、0.24) 的电导率高达 53 GPa 和 600 K。在压力高达25 GPa时，方镁石铁酶的电导率通常随着压力的增加而增加，而方镁石铁酶的活化能和活化体积都随着铁含量的增加而减少。对于 x = 0.07 和 0.10 的样品，电导率最初略有下降，并在 25 至 40 GPa 之间变得恒定，之后随着压力的增加略有增加。对于铁含量较高的样品，电导率在研究的压力范围内随着压力不断增加。如果电导率的这些变化是由于方镁石中铁的等对称高自旋到低自旋转变所致，则这种电导率变化表明自旋转变压力随着方镁石中铁含量的降低而显着降低。由于与含铝钙钛矿共存的方镁石中铁的含量似乎少于无铝钙钛矿中的铁含量，因此自旋跃迁对钙钛矿和方镁石之间铁分配的影响出现在地球下地幔约30-40 GPa的压力范围内。
[1] The pressure-induced electronic spin transition of iron in ferropericlase was investigated as a function of iron content in ferropericlase by in situ electrical conductivity measurement. The electrical conductivity of ferropericlase, (Mg1-x,Fex)O (x = 0.07, 0.10, 0.13, 0.17, 0.24), was measured up to 53 GPa and 600 K using the Kawai-type multianvil apparatus equipped with sintered diamond anvils. At pressures up to 25 GPa, the electrical conductivity of ferropericlase generally increases with increasing pressure, and both the activation energy and activation volume of ferropericlase decrease with increasing iron content. For the samples with x = 0.07 and 0.10, the electrical conductivity shows a slight initial decrease and becomes constant between 25 and 40 GPa, upon which it increases slightly as the pressure increases. For the samples with higher iron content, the electrical conductivity constantly increases with pressure over the investigated pressure range. If these changes in the electrical conductivity are due to the isosymmetric high- to low-spin transition of iron in ferropericlase, this conductivity change suggests that the spin transition pressure significantly decreases with decreasing iron content in ferropericlase. Because the amount of iron in ferropericlase that coexists with the Al-bearing perovskite seems to be less than that in the Al-free perovskite, the influence of the iron partitioning between perovskite and ferropericlase by the spin transition appears in a pressure range of about 30–40 GPa in the lower mantle of the Earth.