Role of Cr super(3+) ions on the microstructure development, and magnetic phase evolution of Ni sub(0.7)Zn sub(0.3)Fe sub(2)O sub(4) ferrite nanoparticles

• Published in: Journal of alloys and compounds 2012-01, Vol.512 (1), p.316-322
• Main Authors: Birajdar, A A, Shirsath, Sagar E, Kadam, R H, Patange, S M, Lohar, K S, Mane, DR, Shitre, A R
• Format: Article
• Language: English
• Subjects: Alloys; Coercive force; Crystallites; Ferrite; Magnetic permeability; Magnetization; Mathematical models; Permeability
• ISSN: 0925-8388
• DOI: 10.1016/j.jallcom.2011.09.087

A series of ferrite samples with the chemical formula Ni sub(0.7)Zn sub(0.3)Cr sub(x)Fe sub(2-x)O sub(4) (x = 0.0-0.5) were prepared by a sol-gel auto-combustion method and annealed at 600 degree C for 4 h. The resultant powders were investigated by various techniques, including X-ray diffractometry (XRD), vibrating sample magnetometry (VSM), and permeability studies. The prepared samples have a cubic spinel structure with no impurity phase. As the Cr super(3+) content x increases, bulk density and crystallite size decrease, whereas porosity increases. The saturation magnetization decreases linearly from 58.31 to 42.90 emu/g with increasing Cr super(3+) content. However, coercivity increases with increasing Cr super(3+) substitution. The magnetic moments calculated from Neel's molecular-field model are in agreement in the experiment results. The initial permeability ( mu sub(i)) decreases with increasing Cr super(3+) substitution. The decrease in initial permeability ( mu sub(i)) is attributed to decrease in magnetization on addition of Cr super(3+). The real part of the permeability decreases gradually with increasing frequency in accordance with Snoek's law. The Curie temperature decreases linearly with increasing Cr super(3+) content.