Magnetic Properties And GMI Effect Of Transition Metal Alloy Microwire Arrays Based On Silicon Microchannel Plate

Over the last two decades,people have been studying on giant magneto-impedance(GMI)in wires,ribbons and thin films with micron scales,and apply them extensively in the fields of industry,life,aerospace,etc.However these structures are relatively large in scale,high cost and difficult to integrate.The working frequency is usually above MHz.Silicon microchannel plate(Si-MCP)is an array structure consisting of a large number of pipes.We fabricate magnetic microwires(microtubes)array based on Si-MCP and study the GMI effect for future preparation of the new GMI sensor with low working frequency and compatible with the integrated circuit process.In this paper,the fabrication process of Fe-Ni alloy microwires array electrodeposited on Si-MCP is studied.In addition,the surface morphology,lattice structure,material composition,magnetic properties and GMI effect of Fe-Ni microwires array have been analyzed and discussed.The effect of annealing on the performance of Fe-Ni microwires array has been studied.The results reveal that the microwires array shows significant magnetic anisotropy,and the biggest GMI is 9.5%when the frequency is 10 kHz.As the annealing temperature increasing,the GMI curve becomes cluttered,especially when the sample is annealed at 300℃,the GMI is fluctuated at-5%～0,and there’s no obvious GMI effect.The CoNiFe microtubes array is prepared by elecreoless deposition based on Si-MCP.The surface morphology and structure of the.mivrotubes array are observed and analyzed.The magnetic properties and GMI effect with different deposition time and different dimethylaminoborane(DMAB)concentration are studied.When DMAB concentration is 0.07 mol/L and the deposition time is 10 min,the best GMI performance is obtained.The max GMI of 10 kHz reaches 97%,which is much higher than that of the Fe-Ni microwires array.At last,Cu/CoNiFe/Si-MCP composite structure was prepared by liquid flow deposition based on CoNiFe/Si-MCP.The results show that Cu/CoNiFe/Si-MCP composite structure has stronger magnetic anisotropy than CoNiFe/Si-MCP,and GMI can reach 75%,which is significantly higher than that of CoNiFe/Si-MCP(43%).This provides experimental evidence for the development of 3-D magnetic devices with higher GMI effect based on silicon microchannel plate.