PHYSICAL-PROPERTIES OF THE GIANT MAGNETORESISTIVE PEROVSKITE SYSTEM LA-ER-CA-MN-O

The effect of minor changes in lattice parameters and Mn3+/Mn4+ ratios on the magnetoresistive and related properties df the La-Er-Ca-Mn-O p erovskite system have been investigated. The latter is found to be the more important factor in determining the magnetotransport properties of these materials. One composition has been prepared by both the stan dard ceramic method as well as a sol-gel technique. Although the gener al features of the magnetotransport properties of these two samples we re very similar, the magnetic properties showed significant difference s. Experimental results are explained on the basis of a spin-dependent mechanism which is related to lattice distortion.