Structural and magnetic Properties of TbZn-substituted calcium barium M-type nano-structured hexa-ferrites

Effect of TbZn substitution on the structural and magnetic properties of Ca0.5Ba0.5-xTbxZnyFe12-yO19, (x = 0.00-0.10; y = 0.00-1.00) ferrites prepared by sol-gel auto combustion is reported. The synthesized samples were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and Vibrating Sample magnetometery. The X-ray diffraction analysis confirmed single phase M-type hexa-ferrite structure. The lattice parameters were found to increase as TbZn contents increases, which is attributed to the ionic sizes of the implicated cations. The TbZn seems to be completely soluble in the lattice. The results of scanning electron microscopy and transmission electron microscopy shows that the grain size decreases with increase of TbZn substitution. The coercivity values (1277-2025 Oe) of all samples lies in the range of M-type hexa-ferrite and indicate that an increase of anisotropy was achieved by substitution of TbZn, while the size of nanoparticles was drastically reduced between 18 and 25 nm. The increased anisotropy and fine particle size are useful for many applications, such as improving signal noise ratio of recording devices. (C) 2013 Elsevier B. V. All rights reserved.