The enhancement in magnetic properties of exchange-coupled (1−x) BaFe12O19/ x Y3Fe5O12 magnetic nanocomposite film

Abstract

The BaFe12O19/Y3Fe5O12 nanocomposite magnet film with various soft phase (YIG) compositions has been synthesized by a sol–gel method followed by a spin coating technique and annealed at 900 °C for 2 h. The microstructure, surface morphology, film thickness and magnetic properties were investigated by using X-ray diffraction analysis, Raman spectroscopy, field-emission scanning electron microscope, transmission electron microscopy and vibrating-sample magnetometer. The microstructural analysis shows that both phases are present in the nanocomposite film as the soft phase content increases, however, the nanocomposite film crystallinity decreases at higher soft phase content. The morphology of nanocomposite film experience evolution as soft phase composition increase. The grain size of the nanocomposite film decreases with the soft phase content increment where the average grain size is between 72.13 nm and 81.43 nm. The magnetic properties and the magnetic energy product of the nanocomposite film were enhanced by a 10 % addition of soft phase into the nanocomposite film. The values are higher than the magnetic properties of the single hard magnetic phase (BaM). This improvement corresponds to the exchange- interaction that was achieved in soft-hard phase grains. Further increment in the soft phase causes the magnetic properties to be reduced, lower than the single hard phase magnetic properties due to competition from dipolar interaction (soft–soft), suppressing the soft-hard interaction. The best nanocomposite (BaM/YIG) film with good magnetic properties exhibited by the film with 10 % of soft phase, with an energy product value of 8.14 kJ/m3 at room temperature and 15.74 kJ/m3 at 10 K. The Curie temperature is 740 K for single BaM phase film and 730 K for nanocomposite film at 10 % YIG composition.