Influence of magnesium oxide nanoparticles embedded in Bi-2212/Ag tapes on their superconducting properties

A MgO-doped Bi$_2$Sr$_2$CaCu$_2$O$_y$ (Bi-2212) high-temperature superconductor is investigated experimentally. The influence of the MgO particle concentration and size on the high-temperature superconductivity parameters is studied. It is shown that, when incorporated into the superconductor, MgO particles do not change their structure. The optimal parameters of the particles exerting the strongest effect on the material are found. The optimal size of the particle is in the range 40–50 nm for a cubic structure. Measures should be taken against clustering. Ways of particle preparation and incorporation into the superconductor are considered. The superconductivity of the material with embedded MgO particles is investigated. At temperatures close to 20 K, the magnetic field of doped tapes exceeds that of undoped ones by a factor of 2.5–10.0 depending on the MgO concentration. The temperature dependences of the superconducting properties of the doped tapes at different magnetic fields are presented.