Anomalous suppression of Nernst effect in La0.7Ca0.3MnO3

We report on the magnetization, colossal magnetoresistance (CMR), thermoele ctric power (TEP) and Nernst coefficient (Q) measurements of a La0.7Ca0.3Mn O3 bulk ceramic sample (T(c)similar to 265 K), The semiconductor-metal tran sition near T-c is attributed to an increase in the hole density. For T les s than or equal to T-c, an anomalous suppression of the Nernst coefficient was observed when the field increased from 0.38 to 1.8 T. The data suggest a field increased mobility of the charge carriers as a principal cause for the CMR. (C) 1999 Elsevier Science Ltd. All rights reserved.