Abstract

A series of polycrystalline samples with nominal compositions Fe_1.02 – xPd_xSe_0.5Te_0.5 (x = 0, 0.02, 0.05, 0.1, 0.15, 0.2) has been synthesized and studied by means of the X-ray diffraction, scanning electron microscopy, electrical resistivity and magnetization measurements. An increase in the Pd content above x = 0.02 leads to the phase segregation and the appearance of a non-superconducting tetragonal FeSe-like phase and a PdTe-type hexagonal phase along with the superconducting FeTe-like phase. The unit cell volume of the FeTe-like and FeSe-like phases is observed to increase and decrease, respectively, when the Pd content increases. Such a behavior is ascribed to the redistribution of selenium and tellurium between coexisting phases. It has been shown that the revealed changes in the composition and volume fraction of the superconducting FeTe-like phase with increasing Pd content are the main reason for the decrease in the critical temperature and critical current density in Fe_1.02 – xPd_xSe_0.5Te_0.5.

中文翻译：

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钯取代铁在Fe 1.02 Se 0.5 Te 0.5中引起的相分离和超导性能的变化

摘要

通过X射线衍射，扫描电子显微镜合成和研究了一系列名义成分为Fe _{1.02 –  x} Pd _x Se _0.5 Te _0.5（x = _{0，0.02，0.05，0.1，0.15，0.2）}的多晶样品。，电阻率和磁化强度测量。Pd含量增加到x以上= 0.02导致相分离，并出现非超导四方FeSe样相和PdTe型六方相以及超导FeTe样相。当Pd含量增加时，观察到FeTe样相和FeSe样相的晶胞体积分别增加和减少。这种行为归因于硒和碲在共存相之间的重新分布。研究表明，随着Pd含量的增加，超导类FeTe相的组成和体积分数的变化是Fe _{1.02 –  x} Pd _x Se _0.5 Te临界温度和临界电流密度降低的主要原因。_0.5。