Influence of Dy3+ doping on Mössbauer, magnetic and microwave absorption properties of M-type Ba0.5Ca0.5DyxFe12-xO19 hexaferrites

Abstract

The present research paper reports a systematic study of the magnetic, and structural properties of Ba_0.5Ca_0.5Dy_xFe_12-xO₁₉ M-type hexaferrite. The dysprosium was doped @ x  = 0 − 0.2, keeping Δx = 0.05, in BCDF by the sol–gel self-ignition technique. The sintering of the synthesized samples was performed for 4 h at 1050°C. The crystallographic analysis of the samples was made from the X-ray diffractograms (XRD), while the morphological and elemental analysis was made from field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray spectroscopy (EDAX) profiles. The structural results revealed the formation of the M-type hexaferrite having P6₃/mmc as a space group along with the co-existence of a secondary Fe₂O₃ phase. FESEM micrographs exhibit the hexagonal platelets randomly arranged with agglomerations at some places giving rise to the random variations in particle size with varying ’x’. Magnetic measurements (VSM) show that the saturation magnetization (M_S) and coercivity (H_C) increase with the increasing Dy³⁺ doping pointing towards the fact that the Dy doping in Ba-Ca ferrite can be used to fabricate the hard ferrites with good saturation magnetization. The Mössbauer spectrum recorded at room temperature reveals five superimposed sextets representing the five Fe³⁺ ion sites. Investigating the Microwave absorption (MWA) characteristics in the frequency range 8 − 12 GHz (X-band), reveals that the sample with x  = 0.1 having 3 mm thickness possesses good MWA power. Its minimum RL value for matching frequency 10.06 GHz is approximately −26.96 dB, indicating that more than 90 % of microwaves are absorbed. The current work offers the Dysprosium-doped BCDF hexaferrites, as promising candidates for microwave absorption applications.