Shift of superconducting transition temperatures in "magnetic superconductor" RuSr₂(Eu₁.₅Ce₀.₅)₁₀₋δ under influence of annealing in high pressure oxygen atmosphere

Abstract

Effect of annealing in high pressure oxygen atmosphere on superconducting transition temperatures for ceramic samples of magnetic superconductor RuSr₂(Eu₁.₅Ce₀.₅)₁₀₋δ was studied. It was shown that properties of the samples are consistent with behavior of the granular superconducting system. As a result of oxygen saturation the superconducting transition temperatures become higher. Particularly, shift of the superconducting transition temperature for intergranular medium is ΔTci = 9.2 K and for the matter within the granules ΔTcg = 6.8 K. This difference is due to the mechanism of oxygen diffusion along the grain boundaries. In the temperature range of 135 < T < 350 K the resistance behavior obeys the Mott's law of variable range hopping for three-dimensional case.