• DocumentCode
    1531791
  • Title

    Structure and thermomagnetic properties of new FeCo-based nanocrystalline ferromagnets

  • Author

    Johnson, F. ; Hughes, P. ; Gallagher, R. ; Laughlin, D.E. ; McHenry, M.E. ; Willard, M.A. ; Harris, V.G.

  • Author_Institution
    Dept. of Mater. Sci. & Eng., Carnegie Mellon Univ., Pittsburgh, PA, USA
  • Volume
    37
  • Issue
    4
  • fYear
    2001
  • fDate
    7/1/2001 12:00:00 AM
  • Firstpage
    2261
  • Lastpage
    2263
  • Abstract
    FeCo-based ferromagnetic alloys (HITPERM variants) of composition Fe44.5Co44.5Zr7B4, Fe44 Co44Zr5.7B3.3Ta2Cu 1, Fe44Co44Zr5.7B3.3 Mo2Cu1, and Fe37.2Co30.8 Zr7B4Cu1 were prepared by melt-spinning amorphous precursors, followed by nanocrystallization. Samples were characterized using vibrating sample magnetometry (VSM), X-ray diffraction (XRD), and differential scanning calorimetry (DSC). VSM was used to measure magnetization vs. temperature from 370-1260 K. Magnetic data showed structural and magnetic phase transitions including primary and secondary crystallization events and the to a structural phase transition in FeCo nanocrystals. Ta and Mo were observed to suppress the to a transition temperature of FeCo. The Fe:Co 65:35 alloy exhibits significant curvature in M(T) indicating proximity of the ferromagnetic to paramagnetic transition and the α to γ transition. XRD phase analysis identified crystallized phases as α-FeCo, (Fe, Co)3Zr, in agreement with previous reports for unmodified HITPERM alloys. DSC data, analyzed using the Kissinger technique, indicated that the removal of Cu from the original HITPERM composition increased the activation energy for primary crystallization, whereas Ta and Mo substitutions decrease the activation energy
  • Keywords
    X-ray diffraction; cobalt alloys; crystallisation; differential scanning calorimetry; ferromagnetic materials; ferromagnetic-paramagnetic transitions; iron alloys; magnetisation; nanostructured materials; soft magnetic materials; solid-state phase transformations; α-to-γ transition; 370 to 1260 K; Fe37.2Co30.8Zr7B4Cu 1; Fe44.5Co44.5Zr7B4; Fe44Co44Zr5.7B3.3Mo 2Cu1; Fe44Co44Zr5.7B3.3Ta 2Cu1; HITPERM; Kissinger technique; X-ray diffraction; activation energy; crystallization; differential scanning calorimetry; ferromagnetic-to-paramagnetic transition; magnetic phase transition; magnetization; melt spinning; nanocrystalline ferromagnetic alloy; soft magnetic properties; structural phase transition; thermomagnetic properties; vibrating sample magnetometry; Amorphous magnetic materials; Amorphous materials; Cobalt alloys; Copper alloys; Crystallization; Iron alloys; Temperature; X-ray diffraction; X-ray scattering; Zirconium;
  • fLanguage
    English
  • Journal_Title
    Magnetics, IEEE Transactions on
  • Publisher
    ieee
  • ISSN
    0018-9464
  • Type

    jour

  • DOI
    10.1109/20.951142
  • Filename
    951142
    • Link To Document
    https://search.isc.ac/dl/search/defaultta.aspx?DTC=49&DC=1531791