Effect of processing temperature on the superconducting properties of acetone doped MgB2 tapes

Correlation of phase formation, critical transition temperature Tc, microstructure, and critical current density Jc with sintering temperature has been studied for acetone doped MgB2/Fe tapes. Sintering was performed at 600–850 °C for 1 h in a flowing Ar atmosphere. High boron substitution by carbon was obtained with increasing the sintering temperature; however, the acetone doped samples synthesized at 800 °C contain large size MgB2 grains and more MgO impurities. Incomplete reaction for the acetone doped samples heated at 600 °C result in bad intergrain connectivity. At 4.2 K, the best Jc value was achieved in the acetone doped sample sintered at 700 °C, which reached 24,000 A/cm2 at 10 T and 10,000 A/cm2 at 12 T, respectively. Our results indicate that the small grain size and less impurity were also important for the improvement of Jc–B properties besides the substitutions of B by C.