Structure, Spectra, Morphology, and Magnetic Properties of Nb5+ Ion-Substituted Sr Hexaferrites

Abstract

SrFe12−xNbxO19 (x = 0.00–0.15) was here synthesized by a conventional solid-state reaction method. Thermogravimetry and differential scanning calorimetry curves revealed the sample reactions at four temperature ranges, and the optimal reaction stability was obtained at 1240 °C. A single-phase polycrystalline form of SrFe12O19 was obtained until the substitution reached 0.09, and the average crystallite size was found to be in the range of 44.21–60.02 nm. According to Fourier-transform infrared spectra, the formation of Fe–O bonds occurred at 69 and 450 cm−1 in the M-type ferrite, while Raman spectra revealed that all the peaks in the sample corresponded to Raman vibration modes and M-type structures. Through the shift of the peaks, it is speculated that Nb5+ enters into the lattice. The hysteresis loops of the samples were measured by vibrating-sample magnetometry, and the calculated results demonstrated that the coercivity increased with increases in the doping amount (686.3 Oe). At the same time, the saturation magnetization remained at a large value (>72.49 emu/g), which has rarely been reported.

Green synthesis of M-type manganese-substituted strontium hexaferrite SrMnxFe12−xO19 nanoparticles with intrinsic antibacterial activity against human pathogenic bacteria

“…65 Similarly, the chemical composition, the calcination temperature, the route of fabrication, the magneto-crystalline anisotropy, the grain particle size, and the pH of fabrication might have been influencing the hysteresis loops of the HFs. 53,66 As seen in Table 1, the values of M s and M r are significantly higher in SMHF-P and SMHF-L compared to SMHF-C. Therefore, the value of H c in SMHF-L would be greater than that in both SMHF-P and SMHF-C.…”

“…Furthermore, the PXRD data revealed weak and wide reflections, which might be attributed to the presence of surface functionalization of SMHF NPs with bioorganic materials used in the preparation process. 29,50,51,53…”

“…Furthermore, the PXRD data revealed weak and wide reflections, which might be attributed to the presence of surface functionalization of SMHF NPs with bioorganic materials used in the preparation process. 29,50,51,53 The average size of the SMHF NPs was determined to be 30 nm using the Debye-Scherrer equation, based on the full width at half maximum (FWHM) values of the main peaks. The Williamson-Hall plot method, as shown in Fig.…”

Single-Domain Hard Ferromagnetic M-SrFe Nanoparticles for Magnetic Data Storage

“…The 922 0 C range is where 0.76% of weight loss happens. The final stage of weight loss involves heating Fe2O3 to produce SrFe12O19, where 4.05% of the weight is reduced as a result of the temperature rising to 1209 0 C [49]. On the metric scale, M-SrFe Nps has a melting point of >450 0 C. The melting point of M-SrFe Nps was measured at 583 0 C by DTA.…”