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采用有机合成的方法制备配位化合物FeSe2粉末,然后将该前驱粉末在650℃下真空环境退火得到β-FeSe0.93粉末,经烧结最终制得具有超导性能的FeSe0.93体材料。采用扫描电镜、X射线衍射及能谱仪对两种粉末进行了成分和形貌分析,结果表明,化学合成得到的FeSe2粉末颗粒呈八面体状,粒度均匀,尺寸约0.5μm。而FeSe2粉末经高温退火后发生分解,铁硒比随着硒单质的逸出而增大,最终获得粉末成分为FeSe0.93,颗粒发生融合使得粒度增大,由于分解反应的无序性使得产物中有少量的非超导相(α-FeSex)。粉末经压制成锭后750℃下烧结,对FeSe0.93粉末制块材进行了超低温下电输运测量的研究,多物性测量系统(PPMS)测试结果表明该体材料初始超导转变温度(Tc,onset)约为11 K,同时存在零电阻特性(Tc,0=4 K),超导性能得到较好的表现。因为非超导的杂相存在对铁硒化学计量比产生微扰,没能获得更好的输运测量结果。
The coordination compound FeSe2 powder was prepared by the method of organic synthesis, then the precursor powder was annealed in vacuum environment at 650 ℃ to obtain the powder of β-FeSe0.93. Finally, the FeSe0.93 material with superconductivity was obtained by sintering. The composition and morphology of the two powders were characterized by scanning electron microscopy, X-ray diffraction and energy dispersive spectroscopy. The results showed that FeSe2 powder synthesized by chemical synthesis was octahedron with uniform particle size of about 0.5μm. However, the FeSe2 powder decomposed after annealing at high temperature, and the iron-selenium ratio increased with the release of selenium. The final powder composition was FeSe0.93. The particle size increased due to the fusion of the particles. Due to the disorder of the decomposition reaction, the product There is a small amount of non-superconducting phase (α-FeSex). Powder was pressed into ingot and sintered at 750 ℃, the FeSe0.93 powder bulk ingot was measured at low temperature. The multi-physical property measurement system (PPMS) test results showed that the initial superconducting transition temperature (Tc , onset) is about 11 K, and at the same time there is a zero-resistance characteristic (Tc, 0 = 4 K), and the superconductivity performance is better. Because non-superconducting hetero phases present perturbations in the stoichiometric ratio of iron and selenium, better transport measurements are not obtained.