We prepared a series of Mg 1-xZr xB 2 bulk samples with different x values by the solid-state reaction at ambient pressure and investigated the effects of the Zr doping on phase compositions, microstructure, and flux pinning behavior. The results indicate that the a axis increases with the increase of the Zr doping and the c axis remains unchanged. ZrB 2 phases form and a small amount of Zr atoms may substitute Mg in Zr-doped samples. Critical temperature drops with increasing the Zr doping. It is found that critical current density J c can be significantly enhanced by the Zr doping and the best data are achieved in Mg 0.9Zr 0.1B 2. For this sample, J c values are remarkably improved to 1.83×10 6A/cm 2 in the self field and 5.51×10 5A/cm 2 in 1 T at 20 K. Also, the irreversibility field is increased by the Zr doping. The high density, fine grain size of MgB 2, and small ZrB 2 particles in Zr-doped samples may be responsible for the enhancement of J c. Also, the field dependence of J c at different temperatures was briefly discussed.
ASJC Scopus subject areas
- Physics and Astronomy(all)