Electrical transport properties of manganite powders under pressure

M. G. RODRÍGUEZ; A. G. LEYVA.; C. ACHA

Buenos Aires

Congreso; At the frontiers of Condensed Matter V; 2010

CAC-CNEA

We have measured the electrical resistance of micrometric to nanometric powders of the La5=8¡yPryCa3=8MnO35=8¡yPryCa3=8MnO3 (LPCMO with y=0.3) manganite for hydrostatic pressures up to 4 kbar. By applying di®erent ¯nal thermal treatments to samples synthesized by a microwave assisted denitration process, we obtained two particular grain characteristic dimensions (40 nm and 1000 nm) which allowed us to analyze the grain size sensitivity of the electrical conduction properties of both the metal electrode interface with manganite (Pt / LPCMO) as well as the intrinsic intergranular interfaces formed by the LPCMO powder, conglomerate under the only e®ect of external pressure. We also analyzed the e®ects of pressure on the phase diagram of these powders. Our results indicate that di®erent magnetic phases coexist at low temperatures and that the electrical transport properties are related to the intrinsic interfaces, as we observe evidences of a granular behavior and an electronic transport dominated by the Space Charge limited Current mechanism.