Cryogenic hysteretic loss analysis for (Fe,Co,Ni)–Zr–B–Cu nanocrystalline soft magnetic alloys

Abstract

The present study compares the hysteretic losses of a series of eight nanocrystalline soft magnetic alloys with compositions (Fe,Co,Ni)-Zr-B-Cu. The alloys were produced by a single wheel melt spinning technique followed by isothermal annealing to promote primary crystallization. As determined by x-ray diffraction experiments, these samples consist of fcc and/or bcc crystallites with average grain diameters of less than 15nm. Vibrating sample magnetometry was employed to measure hysteresis loops at 110 and 300K. The integrated hysteresis loops were larger for the (Fe0.22Ni0.78)89−xZr7B4Cux alloys and nearly unchanged for the other alloys with one exception [i.e., (Fe0.75Co0.125Ni0.125)85.5Zr8.5B5Cu1]. Additional hysteresis measurements with varying degrees of maximum flux density (between 0.03 and 1.1T) were performed at 110 and 300K for the alloy with composition (Fe0.75Co0.125Ni0.125)85.5Zr8.5B5Cu1, annealed at 823K for 1h. A 50% reduction in hysteretic losses was observed for this sample when measured at 110K (compared to room temperature).

Crystal Structure and Magnetic Properties of (Fe,Si,Al)-Based Nanocomposite Magnets Designed for Cryogenic Applications

“…Other materials designed for room temperature use have also been investigated for cryogenic applications, exhibiting varying degrees of degraded performance. [5][6][7][8][9] With all of the materials investigated showing some performance degradation due to the cryogenic environment, it is clear that there is room for new alloys specifically designed for cryogenic temperatures if ferromagnetic materials are going to be considered for use within the cryostat.…”