Studies on Nanostructure, Magnetic Behavior, Optical Properties, and Magnetic Field Sensor Co_0.2Fe_2.8O₄ Nanofluid

Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Negeri Malang, Malang 65145, Indonesia

^* Corresponding author: arif.hidayat.fmipa@um.ac.id

Abstract

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 Co_0.2Fe_2.8O₄, where Co_0.2Fe_2.8O₄ nanoparticles were synthesized using the coprecipitation method. The XRD results showed that Co_0.2Fe_2.8O₄ 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 Co_0.2Fe_2.8O₄ nanoparticles have been successfully synthesized. Based on the SEM characterization, filler Co_0.2Fe_2.8O₄ is composed of spherical nanoparticles and tends to agglomerate. The optical properties of Co_0.2Fe_2.8O₄ are characterized by a band gap value of 2.87 eV. Furthermore, the Co_0.2Fe_2.8O₄ nanofluid has also been tested for magnetic field sensors. Interestingly, the lux intensity value is 6.6 lux. Based on the results, the Co_0.2Fe_2.8O₄ nanofluid has the potential to be applied as a magnetic field sensor.