Synthesis, Structure, and Properties of Superconductors under the Action of Plasma Shock Waves

摘要

The capabilities of synthesis and compaction of a MgB_2 compound from a mixture of magnesium and boron powders in a metal casing and on a multilayered tape under the action of asubmicrosecond shock wave (SW) generated by the interaction of a high-speed cumulative plasma jet with a solid target are studied. The optimal power of a SW pulse and also the distance between a sample and a plasma anode and the number of plasma pulses are determined. The effect of plasma SW action on the MgB_2 structure and superconducting properties is studied. It is assumed that, as a result of the plasma SW action, point defects (vacancies and interstitial atoms) form in a superconducting matrix. The possibility of SW-induced synthesis of MgB_2 from a mixture of magnesium and boron powders is demonstrated, and an increase in the critical current of the superconductor in an external magnetic field of 2 to 5 T after the plasma SW action is found. The increase in the critical current of high-temperature superconducting tapes under the SW action is explained by an increase in the density of superconducting interlayers, their homogenization, granulating of grains, and strengthening of grain-boundary bonds at the interface with the metal casing.