Application of La1-xMnO3 giant magnetoresistance sensors for testing of high-T-C superconducting tapes

Single-segment magnetoresistive magnetic field sensors based on a giant mag netoresistance (GMR) effect in polycrystalline self-doped La1-xMnO3 films w ere designed, fabricated, and evaluated. Depending upon the deposition temp erature, the low field GMR sensitivity La1-xMnO3 films at liquid-nitrogen t emperature ranged from 0.4 to 0.7%/mT. A method, based on the measurement o f persistent low magnetic held near the surface of high-T-c superconducting tape was proposed. The same exciting magnetic held can be used simultaneou sly to generate the eddy currents in the superconducting tape and to reset the sensor before each measurement. This allows to overcome the magnetoresi stance hysteresis in a low magnetic held range. The preliminary results sho w the possibility to use this method for monitoring the quality of BSCCO/Ag superconducting tapes with a tiny filament structure. (C) 2001 Elsevier Sc ience B.V. All rights reserved.