Magnetic anisotropy of LaCo-substituted SrFe12O19 ferrites

Abstract The magnetic anisotropy of LaCo-hexaferrites has been investigated by the use of the singular point detection and the second harmonic techniques in the low-temperature range. Below 200 K a steep rise of the anisotropy field has been observed together with a strong distortion of the magnetization curve which is interpreted as due to a negative K2 and a large positive K3 anisotropy constants. The results are analyzed in terms of an extended Stoner–Wohlfarth model and the obtained values of the anisotropy coefficients χ2,0,χ4,0,χ6,0 are reported versus temperature.