Carboxymethyl cellulose (CMC)/polyvinyl alcohol (PVA)-Mn0.25Fe2,75O4/Ag ferrogels was fabricated by using the freezing-thawing method. Mn0.25Fe2.75O4/Ag magnetic fillers of ferrogels were synthesized by using coprecipitation and chemical reduction methods. Characterization of Mn0.25Fe2.75O4/Ag nanopowders was carried out using X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), Vibrating Sample Magnetometer (VSM) instrument, and antimicrobial activity. At the same time, CMC/PVA-Mn0.25Fe2.75O4/Ag ferrogels were characterized by using magnetothermal instrument. The XRD pattern of the magnetite filler shows the peaks by the Fe3O4 and Ag phases, respectively. The TEM image, there are Mn0.25Fe2.75O4 and Ag with particle size distributions of 5–7 and 10–13 nm, respectively. The hysterical curve from VSM characterization shows a decrease in the value of magnetization saturation from 16.9 to 14.7 emu/g along with the addition of Ag material. Antimicrobial activity was tested using the agar diffusion method. Mn0.25Fe2.75O4/Ag samples showed very good results indicated by the widening of the zone of inhibition around the sample. Thus, CMC/PVA-Mn0.25Fe2.75O4/Ag ferrogels has the potential application to be applied in hyperthermia therapy as well as antimicrobial materials.

Magnetic nanoparticles are a potential material that can be used in a few fields of nanotechnology such as absorbent, catalyst, energy, storage, biomedical, and cancer treatment. Every nanoparticle has different properties, so they will appear unique when two magnetic materials were composited into one unit. Mn0.25Fe2.75O4/NiCo2O4 nanocomposites were successfully synthesized by using simple coprecipitation and sonication methods. To determine the nanostructure and Specificesific Absorption Rate (SAR) value of sample, Mn0.25Fe2.75O4/NiCo2O4 nanocomposites were successfully characterized by using XRD, SEM, and Magneto-thermal instrument, respectively. Based on the data analysis, the XRD profile of Mn0.25Fe2.75O4/NiCo2O4 combining from two phase of Mn0.25Fe2.75O4 and NiCo2O4. By using the Debye Scherer equation, the particle size of Mn0.25Fe2.75O4/NiCo2O4 nanocomposites is about 10.64 nm and presentage of crystallinity is 67.66%. SEM characterization shows that there is agglomeration in the nanocomposites due to the large surface energy between the particles. Properties of superparamagnetic was observed by using VSM, saturation magnetization 17.79 emu/gr and coercivity about 0,15 T. Furthermore, SAR value of Mn0.25Fe2.75O4/NiCo2O4 nanocomposite revealed the optimum value with 0.343 Watt every gram.