Synthesis of hexagonal Co~(3+)-substituted Sr-ferrites via ball- milling assisted ceramic process and their magnetic properties

摘要

M-type hexagonal SrCo_xFe_(12_x)O_(19) (x=0, 0.1, 0.2, and 0.3) have been synthesized by the ball-milling assisted ceramic process. The influence of Co substitutions on the crystalline structure, lattice strain, morphology, and magnetic behaviors has been investigated. The results show that a high-crystallized hexagonal SrCo_xFe_(12_x)O_(19) is obtained when the precursor is calcined at 950 ℃ in air for 3 h. Lattice parame:ers and grain size of SrCo_xFe_(12_x)O_(19) increase with the increase in substitution content (x). Hysteresis behavior varies with substitution content (x) and calcination temperature. M-type hexagonal SrCo_xFe_(12_x)O_(19) (x = 0, 0.1, and 0.2), calcined at 950 ℃, with uniaxial ani-sotropy exhibits a broad M-H loop and rectangular shape. At higher calcination temperature (1050 and 1200 ℃) or substitution content (x) is equal to 0.3, the character of the hysteresis loop of SrCo_xFe_(12_x)O_(19) changes from hard into semi-hard. The tren I of specific saturation magnetization of SrCo_xFe_(12_x)O_(19), calcined at 950 ℃, increases with the decrease in lattice s:rains. SrFe_(12)O_(19), calcined at 950 ℃, has the highest specific saturation magnetization value (91.30 emu/g) and magnetic moment (17.36 μ_B). With the increase of calcination temperature, magnetic domain typernof ferrites changes from a single magnetic domain to a multi-domain type.