LARGE MAGNETORESISTANCE IN POLYCRYSTALLINE LA-Y-CA-MN-O

A large magnetoresistance ratio in excess of 10 000% (at 140 K, H=6 T) has been obtained in a sintered perovskitelike material with a composition of La0.60Y0.07Ca0.33MnOx. The doping of La-Ca-Mn-O with Y resulted in a decrease in the lattice parameter by ∼0.2%, and improved the magnetoresistance by an order of magnitude. The fact that such a large magnetoresistance can be obtained in a polycrystalline material implies that an epitaxial film growth may not be necessary for device applications, with fewer restrictions in substrate selection and processing parameters. Low field measurements at 77 K gave a magnetoresistance ratio of ∼6.5% at H=500 Oe in the La-Y-Ca-Mn-O sample. © 1995 American Institute of Physics.