Effect of strontium doped M-Type bariam hexa-ferrites on structural, magnetic and optical properties

The series of M-type Ba1-xSrx Fe12O19 (x=0.0, 0.2, 0.4, 0.6, 0.8, 1) have been fabricated using powder metallurgy route. The effects of strontium ions have been systematically investigated. The samples are sintered at 1200 degrees C for 2h. The structural properties and surface morphology is determined using X-ray diffraction technique, Fourier Infrared Spectroscopy and Field Emission Scanning Electron Microscope respectively. The magnetic and optical properties are carried out using vibrating sample magnetometer and UV-vis spectroscopy. The XRD analysis revealed that these samples have hexagonal structure. FTIR analysis confirmed that bands in the range 430-590 cm(-1) are due to the stretching vibration of oxygen atom and metal ions (M-O) that is Fe-O confirming the formation of hexa-trrite. The average grain size is determined using FSEM i.e about 0.37-1.5 mu m. The VSM ahalysis showed that saturation magnetization decreased with increasing concentration of Sr+2 ions and this decrease is due to the different site occupation of Sr+2 and Fe+3 ions. The band gap energy decreased with the increasing concentration of strontium ions. This is due to the vacancies of electrons in the valance band of Ba and Sr. The decrease in the distance between conduction and valance band causes the increase in conductivity due to which band gap energy decreases. The widest applications of these hard ferrites permanent magnets are in motors, speakers sensors and MRI systems. (C) 2016 Elsevier GmbH. All rights reserved.