Giant magnetoresistance of La/sub 2/3/A/sub 1/3/MNO/sub 3-8/(A-CA,BA,PB) ) bulk materials preparfd by solid state reaction technique

Since Helmolt [l] and Cbahara [2] respectively reported giant magnetoresistance effect (GMR) of LaBaMnO and LaCaMnO in 1993, the doped manganites have become attractive GMR materials for their potential applications in sensors. Recently manganites’ GMR studies are focused on thin films for the sake of application. However, Hwang [3] showed that LaCaMnO bulk materials presented vcry good low field GMR properties by using heterostructures with soft ferromagnets. Furthermore, polycrystalline bulk materials have notably different GMR effect from epitaxial thin films [4].