10 Computational and Experimental Research in Materials and Renewable Energy (CERiMRE) Volume 3, Issue 1, page 10-18 Submitted : January 2, 2020 Accepted : March 10, 2020 Online : May 2, 2020 doi : 10.19184/cerimre.v3i1.26414 Study of the Ferromagnetic Magnetite Resonance (Fe 3 O 4 ) Forms of Thin Films Using Micromagnetic Simulation Syefira Salsabila 1 , Lutfi Rohman 1,a and Endhah Purwandari 1 1 Departmen of Physics, Faculty of Mathematics and Natural Sciences, Universitas Jember, Jember 68121, East Java, Indonesia a elrohman2@gmail.com Abstract. Fe 3 O 4 is the strongest magnet among other iron oxides. Magnetite Fe 3 O 4 is applied as a permanent magnet. The hysteresis curve of the permanent magnet Fe 3 O 4 has a coercivity field that is not too large so that the material has a good chance to be applied as an absorbent material for RADAR waves. Micromagnetic simulations were carried out on Fe 3 O 4 material in the form of thin film against hysteresis curves and ferromagnetic resonances at various thickness variations and side length variations, and the relationship was seen with changes in the bandwidth of the radar wave absorption frequency if the thickness variation of the simulated material had the same multiple as the experimental material. The thickness variations in this study were 60 nm, 90 nm, and 120 nm, where the variations in the experiment were 0.6 mm, 0.9 mm, and 1.2 mm. Micromagnetic simulation runs were performed to obtain the hysteresis curve and resonance frequency of the Fe 3 O 4 material. The simulation results show that the resonant frequency increases with increasing thickness (fixed side length). Meanwhile, the relationship between the resonant frequency and the side length of the thin film is inversely related. Changes in the resonant frequency of Fe 3 O 4 material are closely related to changes in the absorption frequency band of Fe 3 O 4 material. The hysteresis curve obtained shows that the Fe 3 O 4 material is a hard magnetic material. Changes in the resonant frequency of Fe 3 O 4 material are closely related to changes in the absorption frequency band of Fe 3 O 4 material. The hysteresis curve obtained shows that the Fe 3 O 4 material is a hard magnetic material. Changes in the resonant frequency of Fe 3 O 4 material are closely related to changes in the absorption frequency band of Fe 3 O 4 material. The hysteresis curve obtained shows that the Fe 3 O 4 material is a hard magnetic material. Keywords: Fe 3 O 4 , Ferromagnetic Resonance Frequency, Micromagnetic Simulation Introduction Radar detection technology has grown rapidly every year. This technology has been delivered to a new material, namely Radar Absorbing Material (RAM). RAM is a material that can absorb electromagnetic waves. An object coated with RAM will not be detected by Radio Detection and Raging (RADAR) because this material absorbs reflections and absorbs microwaves. The types of materials used as wave absorbers are dielectric and magnetic material [1]. Magnetic materials depend on magnetic losses. Magnetic losses are a state of loss of the magnetic field of a material and in general this value depends on the magnetic permeability of the material. An example of a material that has high permeability and can be used as an absorber of electromagnetic waves is iron oxide. This material is found in the form of minerals in the form of magnetite (Fe 3 O 4 ), maghemite (γ-Fe 2 O 3 ), and hematite (α-Fe 2 O 3 ). Research on the absorption of electromagnetic waves has been carried out by Shofiyatun experimentally to determine the effect of layer thickness on radar wave absorber [2]. From this research, it was found that the change in the absorption frequency bandwidth of the material to radar waves is proportional to the increase in thickness of the Fe 3 O 4 material.