La-doping effects on pinning properties of MgB 2

Abstract

The La-doped MgB 2 samples were sintered from the mixture of Mg, B and La powder with the mole ratio of Mg:B:La=1.2:2(1+3 x): x, where x was 0, 0.01 and 0.02. The solid reaction of the powder mixture was performed in the microreactor at 1023 K under Ar-atmosphere of 40 MPa. For the prepared samples, the X-ray diffraction results showed the production of impurity phase of LaB 6 nano-particles within the bulk MgB 2 except for small amount of MgO. The slight reduction of T c's and the decreasing of decay rates of J c against the magnetic field could be characterized for x=0.01 sample.