a bulk high temperature superconductor single crystal having the formula mba 2 cu 3 o 7 - x wherein m is selected from the group consisting of y , sm , eu , gd , dy , ho , er , and yb ; and , x has a number value from about 0 . 1 to about 1 . 0 ; are produced by a novel process incorporating : i ) starting powders produced by combustion spray pyrolysis , ii ) a novel setter powder , and / or iii ) a monitored isothermal growth process .