Mechanism Of Transformation Stress Influence On Magnetic Properties Of Sm₂Co₁₇/Fe₇Co₃ Dual-phase Nanowires

Perpendicular magnetic recording method has a broad prospect in the preparation of high density magnetic recording media.Because the magnetic nanowire arrays have a very high perpendicular magnetic anisotropy,they have great potential in the high-density perpendicular magnetic recording media.This paper,using self-made highly order AAO templates,we successfully fabricated Fe₇Co₃ nanowires,single-phase Sm-Co nanowires and Sm-Co/Fe-Co dual-phase nanowires by DC electrochemical deposition method in aqueous solution.And the crystal structure,phase composition,morphology and magnetic properties of nanowires were characterized by the means of XRD,HRTEM,FESEM,EDS and VSM.We also made a tentative explanation for the influence mechanism of the transformation stress in the magnetic properties.The main results are as follows:1.By changing the annealing temperature,we studied the influence of the annealing temperature on the phase and morphology of AAO templates.The results show that after750?annealing,AAO templates turned from the amorphous to the crystalline state and the pore size deeply decreased.The average diameter was reduced from 78.59 nm to 50.53nm.2.The Fe₇Co₃ nanowires with highly ordered and high performance were prepared by self-made AAO templates.When the annealing temperature was 500?,in parallel to the direction of the nanowires,the magnetic properties of Fe7Co3 nanowires were the best,whose major magnetic parameters were as follows:Hc=2017.80 Oe,Mr/Ms=0.76.When the annealing temperature was 660?,in perpendicular to the direction of the nanowires,the magnetic properties of Fe₇Co₃ nanowires were the best.These Fe₇Co₃ nanowire arrays show the following magnetic properties:Hc=1763.80 Oe,Mr/Ms=0.37.Meanwhile,the magnetic shape anisotropy of the nanowire arrays significantly reduced.3.Two molar rations of single-phase Sm-Co nanowires were prepared successfully.We found that after 660?annealing,when themolar rations of Sm and Co was 5:1 in the deposition solution,the single-phase Sm-Co nanowires had more outstanding magnetic properties,in parallel to the direction of the nanowires,which were Hc=2610.10 Oe,Mr/Ms=0.52,in perpendicular to the direction of the nanowires,which were Hc=2509.65 Oe,Mr/Ms=0.43.The magnetic shape anisotropy of the nanowire arrays almost disappeared.4.By changing the alternate time of deposition,we fabricated four different types of Sm-Co/Fe-Co dual-phase nanowires with different contents which were based on the preparing of single-phase Fe7Co3 nanowires and Sm-Co nanowires.The study found that the Sm-Co/Fe-Co dual-phase nanowires,which were prepared by the process III?Fe-Co was deposited in 2 min and Sm-Co was deposited in 15 min?and annealed at 660?,had more excellent properties,whose major magnetic parameters were as follows:Hc=1906.20 Oe,Mr/Ms=0.70.