We report enhancements of magnetoresistance (MR) in granular La0.67Ca0.33MnO3 embedded in SrTiO3. A negative MR is observed with its maximum magnitude near the percolation conduction threshold xc ~ 60% of manganite volume fraction. The maximum in MR vsvolume fraction persists for the entire field range from 5 T down to a few hundred Oersted. We attribute this effect to the amplification of spin-dependent transport at the structural boundaries of the mixture.
PACS numbers: 75.70.Pa, 83.70.Fn, 74.80.-g, 75.50
By: D. K. Petrov, L. Krusin-Elbaum, J. Z. Sun, C. Feild, P. R. Duncombe
Published in: RC21352 in 1998
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