High-pressure synthesis of MgB2 superconductor with T-c above 39 K

We report on the high-pressure synthesis and superconductivity of MgB2 inte rmetallic compounds. The compounds have been obtained through high-pressure sintering of the mixtures of magnesium and boron fine powders under 5.0 GP a and at similar to 1000 degreesC for 30 min. Magnetic measurements using a SQUID magnetometer show the sharp bulk superconducting transition above 39 K; the four-probe de resistivity measurements indicate the highly-conducti ve normal state and sharp superconducting transition. The results highlight that high-pressure synthesis would be a promising way to promote the studi es of this new kind of intermetallic superconductors.