Enhanced Spark plasma sintering in MgB2 added with Ge-Te alloys

• Spark plasma sintered MgB 2 was added with crystalline and amorphous Ge-Te alloys • Densification rate is 3-5 times higher than for pristine, Te and Ge added samples • Densification time from the dwell-beginning is 20 s (Ge-Te) vs. 140-180 s (others) • Sample with amorphous Ge20Te80 has critical current density as for pristine sample • Ge-Te alloys addition promotes formation of MgB 4 , and lowers maximum pinning force Alloys (A) of crystalline Ge50Te50 and partially amorphous Ge20Te80 were added to MgB 2 superconductor. Samples with composition (MgB 2 )A 0.01 were ex situ spark plasma sintered (SPS) and characterized. Results are compared with pristine and Te ((MgB 2 )Te 0.01 ) or Ge, ((MgB 2 )Ge 0.01 ) added samples. Samples with Ge-Te alloys show the fastest densification rate of 3.4 to 5.2 times larger than for the other samples. Although there is a strong influence of Te, alloys synergistically contribute structural and microstructural development and superconducting properties as determined by magnetometry. The proposed methodology of densification curves analysis allows prediction of the final bulk density, MgO and MgB 4 amounts, the amount of carbon substituting boron and critical temperature. The alloys addition promotes MgB 4 formation and a slightly lower critical current density J c for Ge50Te50. For Ge20Te80, J c is approximately similar to pristine sample, while the highest J c is for Te. Samples with Ge-Te have lower maximum pinning force values.