Inter-comparison of electric and magnetic behaviour of superconducting quaternary oxy-pnictide compounds

摘要

Three different oxy-pnictides 'REFeAsO' compounds are prepared by simple and easy solid state single step method. Structural analysis is carried with the help of the X-ray technique and confirms that the obtained samples are phase pure and crystallized in tetragonal P4/nmm structure. Superconductivity is introduced by partial replacement of oxygen by Fluorine in NdFeAsO_(0.8)F_(0.2), SmFeAsO_(0.8)F_(0.2) and PrFeAsO_(0.8)F_(0.2), with highest TC(48K) in NdFeAsO_(0.8)F_(0.2)- SmFeAsO_(0.8)F_(0.2) compound shows the highest upper critical field (Hc2) ～ 377 Tesla, estimated using Ginzburg Landau, (GL). Critical current density doesn't change significantly. The measured MR (magneto resistance) for PrFeAsO is 21.5%, whereas it is 16% for SmFeAsO. Here, we report in brief an inter-comparison of various properties like electric and magnetic transport, magneto-resistance for these synthesized oxy-pnictide compounds.