Synthesis, Characterization, Dielectric and Magnetic Properties of Substituted Y-Type Hexaferrites

A series Manganese and Gadolinium doped Zinc-Strontium hexaferrites, Sr 2 Zn 2 − x Mn x Fe 12− Sr 2 Zn 2 − x Mn x Fe 12−y Gd y O 22 (x = 0.0–1.0, y = 0.0-0.1), was fabricated by chemical co-precipitation route. XRD analysis confirmed the single magnetoplumbite phase formed in hexaferrites with average crystallite size in the range 27–38 nm. Surface morphology and size distribution was also explored using Scanning electron microscopy (SEM). The dielectric parameters i.e. dielectric constant, dielectric loss and dielectic tan loss were measured at ambient temperature and in 1.0 MHz to 3.0 GHz frequency range. Mn-Gd substituted Zn-Sr hexaferrites showed independent trend of dielectric parameters with frequency upto a certain value beyond which resonance type behavior was observed. The dielectric parameters initially decrease with frequency then become almost constant followed by resonance type behavior. Subsitution of Mn and Gd resulted in sharp decrease of dielectric parameters followed by gradual increase. Due to doping to Mn and Gd, saturation magnetization (M s ) and Remenance (M r ) is enhanced whereas the coercivity has been decreased. The squareness ratio of synthesized nanoferrites is less than 0.5.