Study On Giant Magneto-impedance And AC Magnetization Properties Of The Fe Based Composite Structure Soft Magnetic Alloys

In this thesis,three kinds of composite structure soft magnetic alloys were prepared by the chemical deposition and magnetron sputtering methods on Fe67Co18Si11B4 and Fe73.5CulNb3Si13.5B9 soft magnetic alloys.The magnetic properties of samples were strongly improved by annealing.We investigated if the microstructures have an influence on GMI effect and other magnetization properties.The main research contents of this paper were as follows:1.We prepared the Fe67Co18Si11B4/Ni and Fe73.5CulNb3Si13.5B9/Ni composite structures by magnetron sputtering method;we measured the impedance effect by HP4294 A impedance analyzer.We investigated the changes of the samples' magnetic properties and GMI effect upon different thickness and micro-morphology.2.We prepared the Fe73.5CulNb3Si13.5B9/NiP composite structures by chemical deposition method.We measured the GMI,permeability and hysteresis loop by HP4294 A impedance analyzer.We investigated the changes of the samples' magnetic properties and GMI effect upon different thickness and micro-morphology,the micro-morphology were tested by AFM.3.We annealed the Fe73.5CulNb3Si13.5B9 and the Fe73.5CulNb3Si13.5B9/NiP alloy ribbons which were deposited 10 minutes by chemical deposition method.The micro-morphologys were tested by AFM.The effect of stress change on the impedance effect and permeability of alloy ribbons were analyzed.After study,we found that,the magneto-impedance effect of Fe67Co18Si11B4/Ni composite structure alloy ribbons prepared by magnetron sputtering was high to 45.75% when the thickness is 200 nm,which has an order of magnitude improvement than as-cast alloy ribbons,the fmax improve to10 MHz.For the Fe73.5CulNb3Si13.5B9/NiP composite structure alloys prepared by chemical deposition,the value of magneto-impedance effect was 12.9% when f=9.48MHz?Hex=-5.1Oe and thickness is 1.5um,the permeability was high to 2762,quality factor was high to 36.8 when thickness is 2.25 um.The permeability and quality factor have an order of magnitude improvement.The magnetic properties of samples were strongly affected by annealing.This two kinds of surface treatment processes can significantly enhance the magnetic properties,such as permeability,GMI effect and quality factor(Q),which will contribute to its furture application.