Pressure effects on nanostructured manganites

Abstract

We have measured the pressure sensitivity of magnetic properties on La5 / 8 - y Pry Ca3 / 8 MnO3 (y = 0.3) nanostructured powders. Samples were synthesized following a microwave assisted denitration process and a final heat treatment at different temperatures to control the grain size of the samples. A span in grain diameters from 40 nm to ∼ 1000 nm was obtained. Magnetization curves as a function of temperature were measured following different thermomagnetic histories. AC susceptibility as a function of temperature was also measured at different hydrostatic pressures (up to 10 kbar) and for different frequencies. Our results indicate that the nanostructuration plays a role of an internal pressure, producing a structural deformation with similar effects to those obtained under an external hydrostatic pressure. © 2007 Elsevier B.V. All rights reserved.