Exploring the structure, morphology and magnetic perspectives of Al-substituted BaSrPr_0.5Fe_11.5−xAl_xO₁₉ (x = 0.00, 0.6, 1.2, 1.8) hexaferrite nanoparticles

The BaSrPr_0.5Fe_11.5−xAl_xO₁₉ (x = 0.00, 0.6, 1.2, 1.8) hexaferrites are fabricated using an ultrasonic aided citrate sol–gel technique. X-ray Diffraction (XRD) spectra is used to evaluate the size of crystallites and their alteration with substituent, as well as the confirmation of the pure hexaferrite phase. Cell parameter ‘c’ decreased from 23.164 Å to 23.101 Å, while ‘a’ remains almost constant suggesting latitudinal change. Crystallite size decreased from 50.19 nm to 49.08 nm. The sample's morphology demonstrated the uniform distribution of all the grains and the normal platelet hexagonal configuration. Measurements of magnetization revealed ferrimagnetic behaviors for several samples of produced hexaferrites. The saturation magnetization (Ms) and remanence (Mr) found to have decreased from 41.89 to 36.98 emu/g and from 22.37 to 19.98 emu/g, respectively. The magneto-crystalline anisotropy primarily influences the coercivity as the (Hc) value increased from 3.78 kOe to 4.39 kOe as the doping concentration increased. It was revealed that the anisotropy parameter (B) increased and the anisotropy field (Ha) rose from 1.182 kOe to 1.371 kOe with the increase in the doping level. Aluminum-substituted M-type hexaferrites exhibited remarkable coercivity, even at low magnetization, making them promising for use in EMI shielding, microwave devices, sensors, and storage media.