The Preparation And AC-Magnetic Response Of FeZrBCo Soft-Magnetic Nano-Crystalline Ribbons

Sixty years ago,people have found the magnetoimpedance of ferromagenetic thread in magnetic field.But until 1994,the study of giant magnetoimpedance (GMI)effect became more deeper and abroad.In the beginning,people found GMI effect is in non-crystal magnetism materials.For example:soft-magnetic non-crystal thread and ribbons.Subsequently,when people realized the important factors as soft-magnetism of the materials,systematic magnetoanisotropy(intensity,direction and distributing),magnetostretch anisotropy,which influenced the GMI effect,to study difform GMI effect materials with different component,people expanded the research area from Co based non-crystal to Fe based nano-crystal;material's shape was also expanded to many kinds as:multiplex non-crystal thread,coaxal cable multiplex thread,nano-crystalline soft-magnet,spattered film(monolayer and multilayer),sandwich structure film,etc.In order to explain the origin and applied condition in different point of view,many preparation ways are used:annealed in magnetic field,annealed under stress,annealed under torsion,annealed with pyroelectricty and the combination of them.Ppeople's researches have gained lots of prominent success,and developed many useful sensors that have indispensable status in people's production and living during this years.Nano-structured Fe based alloys are well known for their interesting soft magnetic properties expressed by their high permeability,small magnetic crystalline anisotropy,very low coercive field as well as vanishing saturation magnetic strictions when a high-frequency alternating current flows through it.In the last several years various works have reported the giant magnetoimpedance effect in soft magnetic materials such as Fe-Zr-B,Fe-Co-B,Fe-Nb-B and Fe-Zr-B-Cu,Fe-Cu-Nb-Si-B nano-crystalline ribbons which were obtained by annealing amorphous alloys owing to its technological applications in various sensors and heads.However,to our knowledge,up to date there are no published papers on the GMI effect for Fe-Zr-B-Co ribbons yet.In order to explore new kinds of GMI materials as an excellent candidate for technological applications such as magnetic devices or sensors based on GMI effect,In the work presented here,for the first time,The giant magnetoimpedance effect of Fe_89-xZr₇B₄Co_x(x=1,1.5;numbers indicate at.%) Nano-crystalline ribbons prepared by melt-spun with a Cu roller speed of 40m/s has been investigated in detail.The mechanics of GMI effect of it and the dependence of physical factors to it are analyzed too.The giant magnetoimpedance effect was measured by a HP4294A impedance analyzer at room temperature,The experiments reveal that the materials has an optimal annealing temperature,a most effective frequency and a transverse anisotropic magnetic field.The GMI effects of the Fe_87.5Zr₇B₄Co_1.5ribbons can reach the value -45%at f=0.5MHz,H=90Oe,T=700℃; Fe₈₈Zr₇B₄Co₁ ribbons can reach the value -52%at f=0.9MHz,H=90Oe,T=650℃。The transverse anisotropic magnetic fields are respectively at 2Oe-5Oe and 9Oe-12Oe.