FePt Films Fabricated By Electrodeposition

FePt codeposition films and Fe/Pt multilayers were prepared via an electrodeposition process in Na₂SO₄ solution, where FeSO₄·7H₂O and H₂PtCl6·6H₂O solution were used as Fe²⁺source and Pt⁴⁺source, respectively. XRD,SEM,EDX and VSM were used to characterize the morphology and magnetic properties of FePt codeposition films and Fe/Pt multilayers before and after annealing. The detailed researches were given as follows:(1) FePt codeposition films were prepared on pure Cu substrate on condition that the potential changed from -1V to -6V. Fe content increases and Pt content reduces with the decrease of the potential. FePt codeposition film,where the Fe/Pt ratio was close to 1:1,was prepared at the potential of -4.7V. It can be seen from SEM photos that the grain size of the films have relationship with potential. The grain of -4.7V film is uniform and compact, and the surface is smooth,but O content reached to the top,while O content of Fe rich films and Pt rich films is low. Annealed at 550°C for 30 min under H₂ atmosphere, the coercivity and saturation magnetization of the as-prepared FePt film increased from 2.19kA/m to 12.5kA/m, and from 408.6kA/m to 456.3kA/m, respectively.(2) According to the results of FePt codeposition films,-4V,-5V,-6V were chosen as Fe rich layer potential and -2V,-3V,-4V were chosen as Pt rich layer potential. The Fe/Pt multilayers were obtained through the deposits of Fe and Pt reduplicatively.This paper investigated potentials,deposition time,substrates and etc which have effects on Fe/Pt multilayer preparation.The results shows that: When Pt rich layer potential was fixed and Fe rich layer potential was different or Fe rich layer potential was fixed and Pt rich layer potential was different,the multilayers have distinction on the morphology because of the difference of current density,and there is some regularity on the composition of the multilayers.Fe/Pt multilayers which have ideal composition were chosen and annealed at 550°C for 30 min under H₂ atmosphere. After annealing,O is reduced,and Fe,Pt content are improved respectively, grain size of the multilayers is bigger, the coercivity and saturation magnetization of the films are greatly increased.Fe/Pt multilayer(t-2V=12min, t-6V=8min, 2 cycles)has a clear sight of layers.The morphology of this film is fine compared to Fe/Pt multilayers of other deposition time.The adhesion of Fe/Pt multilayer deposited on the conductive glass substrate is less than pure Cu,and the film on glass has a less compact morphology.