Patent ID: 8435473

Claim:
A method for producing the superconducting compound, comprising: dehydrating La 2 O 3 by heating in air, thereby obtaining anhydrous La 2 O 3 ; mixing La metal, TM metal, and Ph element in a ratio of 1:3:3 to obtain a first mixture, wherein TM is one or more selected from Fe, Ru, Os, Ni, Pd, and Pt; and Ph is one or more pnictide elements selected from N, P, As, and Sb, and sintering the obtained first mixture in a dry inert gas atmosphere, thereby obtaining sintered mixture 1 including LaPh, TM 2 Ph, and TMPh; replacing 4-20 mol % of anhydrous La 2 O 3 with mixed powder of LaF 3 and La metal in a ratio of 1:1, thereby obtaining mixture 2 including La 2 O 3 , LaF 3 and La metal; and mixing the sintered mixture 1 and the mixture 2 such that molar ratio of La and TM becomes 1:1 to obtain a third mixture, and sintering the obtained third mixture at 1100-1250° C. in an inert gas atmosphere, thereby obtaining a compound, which is represented by a chemical formula of LaTMOPh, oxygen ions of which are substituted with 4-20 mol % F − ions, forming a superconducting compound of which superconducting transition temperature is controlled in accordance with an ion substitution amount; wherein the superconducting compound has a maximum superconducting transition temperature of 25K or higher.