Magnetoresistive La-Sr-Mn-O powders and films by DAAS technique

摘要

Magnetic perovskites of the general form La_1-xSr-xMnO_3 have successfully been synthesized using deposition by aqueous cetate solution (DAAS). This novel technique, which has the potential for depositing large area thinfilms with high throughput and low cost, involvesthe preparation of an aqueous metal acetate precursor solution, drying the solution to generatea glassy gel, consolidating the gel, and then firing it for short periods of time (<2hrs) to produce crystalline lanthanum strontium manganate (LSMO). The DAAS method has been used to prepare both powders and thin films of LSMO.Powder samples of La_0.83Sr-0.17MnO_3 annealed for 100 minutes at 1200 deg C were high purity, single phase, and exhibited excellent electrical and magnetic characteristics. Thin films of La_0.7Sr_0.3MnO_3 deposited onto both sapphire and stronitum titanate substrates and annealed at 900 deg C were also found to be crystalline, and substrate choice was found to influence thin films crystal structure. These films exhibited sharp metal-insulator transitions, and in the case of LSMO films on strontium titanate, magnetoresistance was observed at the unusually high temperature of approx 360 K.