کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1817488 | 1525694 | 2015 | 4 صفحه PDF | دانلود رایگان |
• We synthesized Co or Ni co-doped (Ca, RE)FeAs2 with RE = La–Gd.
• Co or Ni co-doping improved superconducting properties of all (Ca, RE)FeAs2 samples.
• Tc of (Ca, RE)FeAs2 decreased with decreasing ionic radii of RE3+.
• Eu doped samples showed exceptionally low Tc and long interlayer distance.
• Long interlayer distance of Eu doped samples suggested co-existence of Eu2+ and Eu3+.
Dependence of superconducting properties of (Ca, RE)(Fe, TM)As2 [(Ca, RE)112, TM: Co, Ni)] on RE elements (RE = La–Gd) was systematically investigated. Improvement of superconducting properties by Co or Ni co-doping was observed for all (Ca, RE)112, which is similar to Co-co-doped (Ca, La)112 or (Ca, Pr)112. Tc of Co-co-doped samples decreased from 38 K for RE = La to 29 K for RE = Gd with decreasing ionic radii of RE3+. However, Co-co-doped (Ca, Eu)112 showed exceptionally low Tc = 21 K probably due to the co-existence of Eu3+ and Eu2+ suggested by longer interlayer distance dFe–Fe of (Ca, Eu)112 than other (Ca, RE)112.
Journal: Physica C: Superconductivity and its Applications - Volume 518, 15 November 2015, Pages 14–17