Nanocrystalline soft magnetic ribbons with high relative strain at fracture

Melt-spun nanocrystalline/amorphous composite ribbons (e.g., Finemet and Nanoperm) have excellent soft magnetic properties but are notoriously brittle after crystallization. In this letter, the authors present their findings of increased relative strain at fracture in Co-rich nanocomposite soft magnetic ribbons compared to conventional nanocomposite ribbons. Bending tests of the Co-rich ribbons show relative strain at fracture values more than twice as high as a Nanoperm ribbon. These Co-rich alloys have excellent soft magnetic properties with potential for high temperature applications. A ${\left({\mathrm{Co}}_{0.90}{\mathrm{Fe}}_{0.08}{\mathrm{Ni}}_{0.02}\right)}_{88}{\mathrm{Zr}}_7{\mathrm{B}}_4{\mathrm{Cu}}_1$ ribbon annealed at $823\mathrm{K}$ for $3600\mathrm{s}$ has a high saturation magnetization of $131\mathrm{A}{\mathrm{m}}^2∕\mathrm{kg}$ and a low coercivity of $8\mathrm{A}∕\mathrm{m}$ .