Nanometer MgO particles were introduced into MgB2 tapes prepared by the in situ powder-in-tube process in order to elucidate the influence of this major impurity phase of MgB2 tapes and wires upon the current transport property. The critical temperature, microstructure, flux pinning ability and transport property of MgB2 tapes were studied with respect to the doping contents of nano-MgO particles. It was found that light doping with nano-MgO (less than 2.5wt%) could increase the JC of MgB2 tapes by enhancing the grain connectivity and core density. A 50% enhancement of JC (10T, 4.2K) was obtained upon adding 1.25wt% nano-MgO to MgB2. Further increasing the doping content of nano-MgO would rapidly decrease the critical temperature of MgB2. However, the excess nano-MgO particles could possibly serve as extra pinning centers which improved the JC–B performance of MgB2 at higher temperature and in higher magnetic fields.

Effect of Nanometer MgO Addition on the in situ PIT Processed MgB2/Fe Tapes. C.H.Jiang, H.Hatakeyama, H.Kumakura: Physica C, 2005, 423[1-2], 45-50