Abstract
Characteristic changes occurring in 
superconductors on substituting Sm for Ba have been investigated. An appropriate amount of Sm substitution (
, in the form of 
) promoted grain growth; the grain size became larger than that in the non-substituted sample and had a maximum value at x = 0.07. Single-phase samples were obtained for 
. The critical temperature increased by about 1.5 K for concentrations up to x = 0.02, while it decreased rapidly beyond this amount. Samples did not show superconductivity above 15 K for 
. The crystal structure transformed from orthorhombic to tetragonal at x = 0.3. The average valency of the Cu and the oxygen content decreased linearly with increase of x in the ranges of 
and 
, while they both increased linearly for the range 
.
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