Exchange-spring mechanism of soft and hard ferrite nanocomposites
- Department of Materials Engineering, Indian Institute of Science, Bangalore (India)
- Materials Science Division, Atomic Energy Centre, Bangladesh Atomic Energy Commission (Bangladesh)
Graphical abstract: - Highlights: • Exchange-spring behaviour of soft and hard ferrites was studied. • XRD patterns indicated soft and hard ferrites as fcc and hcp structure. • Hysteresis loops indicate wide difference in coercivity of soft and hard phases. • Nanocomposites produced convex hysteresis loop characteristic of single-phase. - Abstract: The paper reports exchange-spring soft and hard ferrite nanocomposites synthesized by chemical co-precipitation with or without the application of ultrasonic vibration. The composites contained BaFe{sub 12}O{sub 19} as the hard phase and CoFe{sub 2}O{sub 4}/MgFe{sub 2}O{sub 4} as the soft phase. X-ray diffraction patterns of the samples in the optimum calcined condition indicated the presence of soft ferrites as face-centred cubic (fcc) and hard ferrites as hexagonal close packed (hcp) structure respectively. Temperature dependence of magnetization in the range of 20–700 °C demonstrated distinct presence of soft and hard ferrites as magnetic phases which are characterized by wide difference in magnetic anisotropy and coercivity. Exchange-spring mechanism led these nanocomposite systems to exchange-coupled, which ultimately produced convex hysteresis loops characteristic of a single-phase permanent magnet. Fairly high value of coercivity and maximum energy product were observed for the samples in the optimum calcined conditions with a maximum applied field of 1600 kA/m (2 T)
- OSTI ID:
- 22341727
- Journal Information:
- Materials Research Bulletin, Vol. 48, Issue 8; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0025-5408
- Country of Publication:
- United States
- Language:
- English
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