Application of La{sub}(1-x) MnO{sub}3 giant magnetoresistance sensors for testing of high-T{sub}c superconducting tapes

摘要

Single-segment magnetoresistive magnetic field sensors based on a giant magnetoresistance (GMR) effect in polycrystalline self-doped la{sub}(1-x)MnO{sub}3 films were designed, fabricated, and evaluated. Depending upon the deposition temperature, the low field GMR sensitivity la{sub}(1-x)MnO{sub}3 films at liquid-nitrogen temperature ranged from 0.4 to 0.7%/mT. A method, based on the measurement of persistent low magnetic field near the surface of high-T{sub}c superconducting tape was proposed. The same exciting magnetic field can be used simultaneously to generate the eddy currents in the superconducting tape and to reset the sensor before each measurement. This allows to overcome the magnetoresistance hysteresis in a low magnetic field range. The preliminary results show the possibility to use this method for monitoring the quality of BSCCO/Ag superconducting tapes with a tiny filament structure.