Polymer functionalization with manganites

Abstract

We investigated the transport properties of a series of composites made of La 2/3 Sr 1/3 MnO 3 and different copolymers. The temperature dependence of the electrical resistance of the samples is strongly dependent on the nature of the polymers. We found four types of temperature dependences of the electrical resistance: i) simple current dependence of resistivity for poly(methyl-methacrylate-co-styrene) copolymers, ii) single peaked characteristics for poly(acryl amide-co-vinyl acetate), iii) multipeaked dependence found in poly(methyl-methacrylate-co-butadiene) and star type polysiloxane-gstyrene, and iv) current independent characteristics visible in the samples made with linear polysiloxane-based composites.

The effect of artificial boundary grain on the magneto- and electro-transport properties of (1 − x)La0.7Ca0.3MnO3+xA (A=Al2O3 and Ag) nanocomposite

“…In order to find the best-fit parameters at several temperatures, the experimental MR versus H curves were fitted to equation (4). The differentiated curves are fitted by equation ( 6) at T = 5 K for LCMO/Al 2 O 3 and LCMO/Ag composite samples (not shown here).…”

“…The splitting of the e g orbitals is different and, if one orbital moves away from the Fermi level, the double exchange interaction is canceled and the direct super exchange between the core t 2g spins is promoted. As the kinetic energy of the carriers is reduced, the Coulomb repulsion pushes the charge to the outermost layer, thereby generating a barrier to electron transfer between grains [4]. The change in the magnetic interactions does alter the spin stiffness at the surface.…”