Search

The thermoelectric power (TEP) and the electrical resistivity of the intergranular magnetoresistance composite (1-x)La[sub 2/3]Ca[sub 1/3]MnO[sub 3]/(x)yttria-stabilized zirconia (YSZ) (LCMO/YSZ) with x=0%, 0.75%, 1.25%, 4.5%, 13%, 15%, and 80% of YSZ have been measured from 300 down to 77 K. A pronounced TEP peak appears during phase transition for samples with x>0, while it is not observed for x=0. We suggest that this is due to the magnetic structure variation induced by lattice strain which is a result of the LCMO/YSZ boundary layers. The transition width in the temperature derived from dχ/dT, with χ the ac magnetic susceptibility, supports this interpretation. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

TbMnO3 thin films with different crystallographic orientations were deposited epitaxially on LaAlO3 [100] and SrTiO3 [100] single crystal substrates by using pulsed laser deposition. Magnetization measurements were performed along the [110], [-110], and [001] directions of the films. Obvious magnetic anisotropy and low temperature ferromagnetism were found. Transitions at T ∼ 10, 32, 120, and 125 K along different directions are observed. The susceptibility anomalies, remarkably anisotropic, are discussed on the frame of the domain wall and strain-induced distortion. Particularly, the lattice mismatch and the anisotropic thermal expansion between the films and substrates are likely responsible for the distortion behaviors. [ABSTRACT FROM AUTHOR]