Research of weak magnetic penetration into bismuth ceramics

Abstract A method of measurement of quantity of the braiding field on HTSC ceramic patterns has been developed under the condition of Earth magnetic field compensation. Measurements on Fe-doped single-phase patterns of Bismuth ceramics with granular structure and two-step superconducting transition have been carried out. The first critical field H C1 of Josephson medium has been found. It is shown that in the presence of biasing field, which is orthogonal to being measured field and is several times H C1 , the threshold character of magnetic field penetration into Josephson medium remains the same. The results indicate the structural likeness of grains and ceramics as a whole. It is shown the possibility of measuring weak magnetic fields in value from 0 to 2 mT with a resolving power of 0.5 nT.