| Abstract
| - Magnetic nanoscale films have been produced using a batch process based on the decompression of a supercritical CO2/Ferric acetylacetonate (Fe(acac)3) solution near room temperature. Fe(acac)3 was solubilized in supercritical CO2 at 140 bar, and the saturated supercritical solution was decompressed at rates of 1.5 and 45 bar/sec, forming cluster films on both silicon and gold substrates. The resulting nanoscale films have particles in the range of 16 to 350 nm and values of magnetic coercivity in the range 50−115 Oe. These batch films are compared with films grown previously by a continuous free-jet process, using the same supercritical solutions but with decompression times on the order of microseconds. The experiments suggest that the initial restructuring and decomposition of Fe(acac)3 into a magnetically ordered material takes place in the supercritical fluid phase, without influence of the film substrate, well below the known thermal decomposition temperature of 180 °C. This new batch process is straightforward, does not require high-temperature decomposition of a precursor, utilizes nontoxic and inexpensive starting materials, and the CO2 solvent is readily removed by decompression of the supercritical mixture.
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