Bi-based superconductors prepared with addition of CoFe2O4 for the design of a magnetic probe

We have investigated the microstructure and the magnetoresistivity of bismuth based superconductor bulks added with nano-sized CoFe2O4 particles (10 nm in diameter). Samples were prepared through the solid state reaction (SSR) technique by addition of CoFe2O4 nanoparticles during the last step of heat treatment. Phase examination using X-ray diffraction (XRD), morphology investigation by scanning electron microscope (SEM), microstructure and local chemical composition analyses using transmission electron microscope (TEM) coupled with energy dispersive X-ray spectroscope (EDXS), electrical resistance versus temperature ρ(T) under applied magnetic fields (B) and electrical resistance versus B at 77 K, ρ(B), were carried out. The CoFe2O4 added sample shows a great magnetoresistance to weak magnetic field at the temperature of liquid nitrogen (77 K). This result is attractive for practical, because CoFe2O4 added samples can be utilized as active elements in magnetic fields sensor devices.