tailieunhanh - Báo cáo "Effect of the preparation conditions on the properties of Fe-Pt nanoparticles produced by sonoelectrodeposition "

Fe-Pt materials have been widely prepared by vacuum evaporation technique. Recently, chemical and physicochemical methods have been successfully used to make Fe-Pt nanoparticles, thin films. This paper reported another physicochemical method, namely sonoelectrodeposition, to produce Fe-Pt nanoparticles. In the sonoelectrodeposition, the electrodeposition process was assisted with a sonicator. The Ti horn of the sonicator played a role as the cathode on which Fe-Pt nanoparticles were deposited. After a certain time of deposition, a sonic pulse was applied to remove the particles from the Ti cathode. . | VNU Journal of Science Mathematics - Physics 25 2009 1-7 Effect of the preparation conditions on the properties of Fe-Pt nanoparticles produced by sonoelectrodeposition Nguyen Hoang Luong Nguyen Hoang Hai Nguyen Dang Phu Center for Materials Science Faculty of Physics College of Science VNU 334 Nguyen Trai Hanoi Vietnam Received 10 Macrh 2009 Abstract. Fe-Pt materials have been widely prepared by vacuum evaporation technique. Recently chemical and physicochemical methods have been successfully used to make Fe-Pt nanoparticles thin films. This paper reported another physicochemical method namely sonoelectrodeposition to produce Fe-Pt nanoparticles. In the sonoelectrodeposition the electrodeposition process was assisted with a sonicator. The Ti horn of the sonicator played a role as the cathode on which Fe-Pt nanoparticles were deposited. After a certain time of deposition a sonic pulse was applied to remove the particles from the Ti cathode. The composition of Fe-Pt particles can be controlled by changing the concentration of Fe and Pt ions in the electrolyte and the deposition voltage. The particle size can be adjusted by the time of deposition. The as-deposited Fe-Pt nanoparticles were ferromagnetic at room temperature. Upon annealing at 700 C for 1 h under H2 atmosphere the saturation magnetization and the coercivity of the nanoparticles were improved significantly. Sonoelectrodeposition is a promising technique to make large quantity of Fe-Pt nanoparticles. Keywords FePt L10 structure sonoelectrodeposition magnetic nanoparticles hard magnetic materials. 1. Introduction FePt alloy can be in either a disordered face-centered cubic fcc phase in which the statistical distribution of the Fe and Pt atoms is substitutionally random or in a partially or completely ordered face-centered tetragonal fct phase in which Fe and Pt atoms occupy specific sites. The ordered phase can change to the disordered phase and vice versa at elevate temperatures 1 . The fct FePt alloy .