| dc.description |
Bi-2212 tapes were fabricated using a powder-in-tube method and their superconducting properties were measured as a function of heat treatment. The tapes were heated to temperature, T<sub>1</sub> (884-915 °C), and kept at that temperature for 20 min to induce partial (incongruent) melting. The samples were cooled to T<sub>2</sub> with a ramp rate of 120 °C h<sup>-1</sup> and then slowly cooled to T<sub>3</sub> with a cooling rate, R<sub>2</sub>, and from T<sub>3</sub> to T<sub>4</sub> with a cooling rate, R<sub>3</sub>. The tapes were kept at the temperature T<sub>4</sub> for P<sub>1</sub> hours and then cooled to room temperature. Both R<sub>1</sub> and R<sub>2</sub> were chosen between 2 and 8 °C h<sup>-1</sup>. It was found that the structure and J<sub>c</sub> of the tapes depend on the sintering conditions, i.e. T<sub>1-4</sub>, R<sub>1-3</sub> and P<sub>1</sub>. The highest J<sub>c</sub> of 5800 Å cm<sup>-2</sup> was obtained at 77 K in a self-field with heat treatment where T<sub>1</sub> = 894 and 899 °C, R<sub>1</sub> = R<sub>2</sub> = 5 °C h<sup>-1</sup> and P<sub>1</sub> = 6 h were employed. When 0.7% of bend strain, which is equivalent to a bend radius of 5 mm, was applied to the tape, 80% of the initial J<sub>c</sub> was sustained. |
