Title :
Effect of Factors on Coercivity in Sr–La–Co Sintered Ferrite Magnets
Author :
Nishio, Hiroaki ; Minachi, Yoshihiko ; Yamamoto, Hiroshi
Author_Institution :
Sch. of Sci. & Technol., Meiji Univ., Kawasaki, Japan
Abstract :
We varied the composition and sintering temperature of Sr-La-Co ferrite magnets to analyze the effects of various important factors on coercivity (H cJ). We examined the effects of crystal grain size and distribution, the mechanism of magnetization reversal, the degree of crystal grain orientation (OD), and the anisotropy field (H A) on H cJ. We proposed an equation based on the experimental results that expresses the measured H cJ and considers these effects as H cJ = C t(0.4/R h) OD (H A - H d - H in), where C t, R h, H d, and H in are the crystal grain size effects on H cJ of sintered magnet, rotational hysteresis integral corresponding to the mechanism of magnetization reversal, demagnetizing field of shape anisotropy, and interaction field between crystal grains, respectively. We found that apart from the volume ratio for single-domain crystal grains and H A, the mechanism of magnetization reversal had significant effects on H cJ for Sr-La-Co sintered ferrite magnets.
Keywords :
cobalt compounds; coercive force; crystal orientation; demagnetisation; ferrites; grain size; lanthanum compounds; magnetic anisotropy; magnetisation reversal; sintering; strontium compounds; Sr1-xLaxFe12-xCoxO19; anisotropy field; coercivity; crystal grain orientation; crystal grain size; demagnetizing field; magnetization reversal; rotational hysteresis; single-domain crystal grains; sintered ferrite magnets; Anisotropic magnetoresistance; Coercive force; Equations; Ferrites; Grain size; Magnetic analysis; Magnetization reversal; Magnets; Shape measurement; Temperature; Anisotropy field; Sr–La–Co ferrite magnet; coercivity; crystal grain orientation; grain size; magnetization reversal;
Journal_Title :
Magnetics, IEEE Transactions on
DOI :
10.1109/TMAG.2009.2026044
