Effects of Bi-2212 addition on the levitation force properties of bulk MgB2 superconductors

Abstract

We present a detailed investigation of the effects of Bi2Sr2Ca1Cu2O8+kappa (Bi-2212) adding on the levitation force and magnetic properties of bulk MgB2 obtained by hot press method. the amount of Bi-2212 was varied between 0 and 10 wt% (0, 2, 4, 6, 10 wt%) of the total MgB2. Moreover, we present MgB2 bulk samples fabricated by using different production methods including hot pressing method to our knowledge. All samples were prepared by using elemental magnesium (Mg) powder, amorphous nano-boron (B) powder and Bi-2212 powder which are produced by hot press method. As a result of hot press process, compact pellet samples were manufactured. the vertical and lateral levitation force measurements were executed at the temperatures of 20, 24 and 28 K under zero-field-cooled (ZFC) and field-cooled (FC) regimes for samples with various adding levels. At 24 K and 28 K under ZFC regime, the 2 wt% Bi-2212 added sample exhibits a higher vertical levitation force than the pure sample. Bi-2212 added MgB2 samples compared to the pure sample have lower attractive force values in FC regime. the magnetic field dependence of the critical current density J(c) was calculated from the M-H loops for Bi-2212 added MgB2 samples. the 2 wt% Bi-2212 added sample has the best levitation and critical current density performance compared to other samples. the critical temperature (T-c) has slightly dropped from 37.8 K for the pure MgB2 sample to 36.7 K for the 10 wt% of Bi-2212 added sample. the transition temperature slightly decreases when Bi-2212 adding level is increased.