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Sr0.8Ni0.2Fe12−2xMoxO19(x≤ 0.35) nanohexaferrites (NHFs) were obtained by a sol–gel combustion route. The phase identification was performed through X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HR-TEM). The morphological and chemical composition analyses were verified by scanning electron microscope (SEM) and energy dispersive X-rays (EDX), respectively. The crystallite size (DXRD) of all produced samples has been estimated between 31 and 56 nm. Magnetization versus applied magnetic field (M–H) measurements of different products were conducted at 300 K (room temperature, RT) and 10 K, and the results revealed their ferrimagnetic character. Undoped Sr0.8Ni0.2Fe12O19NHFs have the maximum magnetic parameters at both temperatures. 10 K magnetization data such as MS(saturation magnetization), Mr(remnant magnetization), nB(magneton number), and HC(coercivity) belonging to Sr0.8Ni0.2Fe12O19NHFs are MS,max= 99.6 emu/g, Mr,max= 48.2 emu/g, nB,max= 18.83 μB, and HC,max= 3406 Oe, respectively. Moreover, the squareness ratio (SQR = Mr/MS) is 0.489 at RT and 0.484 at 10 K. Those magnitudes assign the single-domain structure with uniaxial crystal anisotropy for this hexagonal product at both temperatures. Some magnetic parameters like coercivities (in a range of (286–475) Oe) and Mr(in a range of (7.8–14.1) emu/g) drop sharply due to the Mo6+doping process. Calculated SQR values are between 0.111 and 0.206, which indicate the multi-domain wall structure for NHFs at both temperatures. Undoped Sr0.8Ni0.2Fe12O19NHFs can be classified as magnetically hard materials, while Mo-doped samples can be classified as soft magnetic materials.

AbstractHere we report the electrospinning synthesis of Cd-substituted Ni-Co ferrite Ni0.5Co0.5-xCdxFe1.78Nd0.02O4(x ≤ 0.25) nanofiber (NFs) with a very low concentration of Nd as a dopant. The structure and surface morphology of the Ni0.5Co0.5-xCdxFe1.78Nd0.02O4(x ≤ 0.25) NFswere analyzed by X-ray powder pattern (XRD), transmission and scanning electron microscopes (TEM) along with Energy-dispersive X-ray (EDX). We have examined the biological applications of the Ni0.5Co0.5-xCdxFe1.78Nd0.02O4(x ≤ 0.25) NFson both cancerous cells and bacterial cells. We have found that Ni0.5Co0.5-xCdxFe1.78Nd0.02O4(x ≤ 0.25) NFsproduced inhibitory action on the human colorectal carcinoma cells (HEK-293) and also showed inhibitory action on the bacterial strains (S. aureus and E. coli) respectively. Finally, this is the first report on the synthesis of Cd- substituted Co–Ni ferrite nanofibers using electrospinning technique exhibiting anti-cancer and anti-bacterial activities.Communicated by Ramaswamy H. Sarma