Effect of mixing three rare-earth elements on the superconducting properties of

Abstract

We report the effect of mixing three rare-earth (RE) elements in the RE site on the superconducting properties of melt-processed , in which RE elements are selected from the group of Nd, Sm, Eu and Gd. The heat treatment profiles for melt processing were determined according to the peritectic decomposition temperatures obtained from the thermal analysis measurements. Microstructural observations and compositional analysis showed that the main phase was (, in which the ratio of three RE elements (R1, R2, R3) was equal to that of the nominal composition, indicating that mixing of RE elements was uniform. All the samples showed relatively high in the range 93.1 - 95.3 K and exhibited the secondary peak effect in the magnetization curves at 77 K with the irreversibility field higher than that of melt-processed Y - Ba - Cu - O. A high value of at 77 K and 2 T was achieved in (Nd, Eu, Gd) for field parallel to the c-axis.