Studies on Nanostructure, Magnetic Behavior, Optical Properties, and Magnetic Field Sensor Co0.2Fe2.8O4 Nanofluid

In recent years, the study of magnetic material-based nanofluids applied as magnetic field sensors has been intensively carried out. This relates to the need for magnetic field sensors to be of great scientific and industrial importance for many applications. Magnetic-based nanofluids are very sensitive to external magnetic fields because they have superparamagnetic properties. In this study, a magnetic field sensor was developed based on nanofluid with filler in the form of Co0.2Fe2.8O4, where Co0.2Fe2.8O4 nanoparticles were synthesized using the coprecipitation method. The XRD results showed that Co0.2Fe2.8O4 has a phase similar to Fe3O4, indicating that the cobalt ions have successfully entered the Fe3O4 system. Furthermore, the results of FTIR characterization showed several primary bonds, namely Co-O and Fe-O, which confirmed that Co0.2Fe2.8O4 nanoparticles have been successfully synthesized. Based on the SEM characterization, filler Co0.2Fe2.8O4 is composed of spherical nanoparticles and tends to agglomerate. The optical properties of Co0.2Fe2.8O4 are characterized by a band gap value of 2.87 eV. Furthermore, the Co0.2Fe2.8O4 nanofluid has also been tested for magnetic field sensors. Interestingly, the lux intensity value is 6.6 lux. Based on the results, the Co0.2Fe2.8O4 nanofluid has the potential to be applied as a magnetic field sensor.