Iron-platinum (FePt) nano-particles were synthesized using a hot metal salt reduction reaction with iron chloride and platinum acetylacetonate as the precursor salts. The synthesis route was based upon work done previously by Sun et Al.. The size and composition of the FePt nano-particles were controlled by varying the surfactant to reagent molar ratio and refluxing time during synthesis. The average size of FePt nano-particles synthesized ranged from 4.08 nm to 5.23 nm. The composition of the nano-particles ranged from Fe60Pt40 to Fe55Pt45. The size was shown to increase as the surfactant to reagent molar ratio was changed from 1:6 to 1:1. The platinum composition increased from 40 % to 45 % with an increase in the refluxing time from 30 minutes to 60 minutes. The X-ray analysis (XRD) showed that the unannealed nano-particles had a FCC crystal structure. The FCC FePt nano-particles were superparamagnetic at room temperature. A blocking temperature (Tb) of 35 K was measured for 5.23 nm Fe55Pt45 nano-particles. Annealing of the Fe55Pt45 nano-particles induced a FCT crystal structure with hard-magnetic properties. Coercivity (Hc) of approximately 13000 Oe was measured at room temperature.
(a) Department of Chemical and Materials Engineering, San Jose State University
(b) Department of Physics and Astronomy, San Jose State University
(c) Department of Biological Sciences, San Jose State University