Thermopower peak in phase transition region of (1-x)La${}_{2/3}$Ca${}_{1/3}$MnO${}_3$/xYSZ

Abstract

The thermoelectric power (TEP) and the electrical resistivity of the intergranular magnetoresistance (IGMR) composite, (1-x)La${}_{2/3}$Ca${}_{1/3}$MnO${}_3$/xYSZ (LCMO/YSZ) with x = 0, 0.75%, 1.25%, 4.5%, 13% 15% and 80% of the yttria-stabalized zirconia (YSZ), have been measured from 300 K down to 77 K. Pronounced TEP peak appears during the phase transition for the samples of x $>$ 0, while not observed for x = 0. We suggest that this is due to the magnetic structure variation induced by the lattice strain which is resulting from the LCMO/YSZ boundary layers. The transition width in temperature derived from $d\chi /dT$, with $\chi$ being the AC magnetic susceptibility, supports this interpretation.

4 pages, 4 eps figures, Latex, J. Appl. Phys 94, 7206 (2003)