Electric and magnetic properties of PMMA/Manganite composites

CELESTE ARTALE; SOLANGE FERMEPIN; MARIANO FORTI; MAURICIO LATINO; MARIANO QUINTERO; LETICIA GRANJA; JOAQUIN SACANELL; GRISELDA POLLA; PABLO LEVY

Centro Atómico Constituyentes, San Martín, Buenos Aires, Argentina

Conferencia; At the Frontiers of Condensed Matter, FCM 2008; 2008

Grupo Materia Condensada, Centro Atómico Constituyentes, CNEA

Several manganite/insulator composites have been extensively studied in order to exploit their magnetic and electrical properties. In this context we explore the use of a polymer as the insulator, which gives the additional advantage of having a flexible sample. In this work, we present the synthesis and characterization of composites of $La_{2/3}Sr_{1/3}Mn_3$ (LSMO) and PMMA. We have obtained samples with different LSMO/PMMA ratio and a pure LSMO to use as a reference. We have performed a study of their structural and morfological characteristics, and their electrical and magnetic properties as a function of temperature and magnetic field.The magnetization results were dominated by the intrinsic LSMO magneticproperties without any appreciable influence related to the PMMA. Resistivity measurements showed an insulating behavior in the whole range of temperatures measured, indicating that the percolation threshold of LSMO grains has not been reached. A significant instability associated to the electric transport through the polymer have been observed. Although the magnetoresistance results of the flexible PMMA samples are large enough to be measured, their MR value is reduced compared to thereference LSMO. In the future we expect to improve the perfomance of this composite working closer to the percolation threshold of the system.