Exchange coupling in SrFe12O19/CoFe2O4 composites: Effect of component proportions

Magnetic interaction in Sr0.7La0.3Fe11.75Co0.25O19–CoFe2O4 composite system: observation, evidence, and influence

“…The magnetic hysteresis loops are recorded using a vibrating sample magnetometer (Quantum Design, Versa lab) with a maximum applied field of ±30 kOe at room temperature. All the diffraction peaks are indexed to the hexagonal (hard) and cubic (soft) symmetry with space group P6 3 /mmc and Fd-3m space group, respectively [12][13][14][15][16][17]. Rietveld refinement of the XRD patterns confirms the existence of two distinct crystallographic phases, and their quantitative phase content, lattice parameters and unit cell volume are given in table 1, and refined patterns are shown in figure 2.…”

“…Figure1illustrates the x-ray diffraction (XRD) patterns of Sr 0.7 La 0.3 Fe 11.75 Co 0.25 O 19 (hard) and CoFe 2 O 4 (soft) composites with various weight ratios of hard:soft = 9:1, 8:2, 7:3, 6:4, and 5:5. All the diffraction peaks are indexed to the hexagonal (hard) and cubic (soft) symmetry with space group P6 3 /mmc and Fd-3m space group, respectively[12][13][14][15][16][17]. Rietveld refinement of the XRD patterns confirms the existence of two distinct crystallographic phases, and their quantitative phase content, lattice parameters and unit cell volume are given in table1, and refined patterns are shown in figure2.…”

“…Most of the reported results show a beewaist-shaped hysteresis loop indicating insufficient exchange coupling of two magnetic phases [7][8][9]. The dominant interaction will depend on morphology, particle distribution, size, and amount of each phase [5,6,[10][11][12]. When both are effectively exchange coupled, the overall magnetization of the composite magnet is higher than that of the hard phase and the coercivity is higher than that of the soft phase [4,7,13].…”