Structural and Electronic Properties of Manganese-Doped Superparamagnetic Iron Oxide Nanoparticles Derived from Natural Iron Sand Kormil Saputra 1,4, Wida Puteri Agista 2,3, Sofiana Aprilia 1, Teguh Ardianto 1, Dian W. Kurniawidi 1, Masruroh Masruroh *4, Didik Rahadi Santoso 4 Ahmad Taufiq 2
1 Physics Study Program, Universitas Mataram, Jl. Majapahit No.62, Gomong, Kec. Selaparang, Mataram, Nusa Tenggara Barat. 83115, Indonesia
2 Physics Department, Universitas Negeri Malang, Jl. Cakrawala No.5, Sumbersari, Lowokwaru District, Malang City, East Java, Indonesia
3 Tinta Emas Institute, Jl. Sultan Salahuddin No.23, Sekarbela District, Mataram, Nusa Tenggara Barat, 83115, Indonesia
4 Physics Department, Brawijaya University, Jl. Veteran No.10-11, Ketawanggede, Lowokwaru District, Malang City, East Java, 65145, Indonesia
Abstract
The development of functional materials based on metal oxides is increasing along with the need for advanced materials for technological, environmental, and medical applications. Indonesia, especially West Nusa Tenggara, has great potential in utilizing iron sand as a natural source of magnetic minerals such as superparamagnetic Iron Oxide Nanoparticles (SPION). This study has successfully synthesized SPION (MF1) and manganese-doped Fe3O4 (Mn0.25Fe2.75O4/MF2) materials from local iron sand using a modified coprecipitation method. The synthesis process involves magnetic separation, dissolution with HCl, precipitation using NH4OH, and doping with MnCl3. Characterization using XRD, FTIR, and UV-Vis shows that both materials have a cubic spinel structure with significant changes in lattice parameters and crystallite size after Mn doping. FTIR spectrum confirmed the presence of O-H, C-O, Fe-O, and Mn-O functional groups, while UV-Vis results showed a decrease in the gap energy from 3.11 eV to 3.07 eV and a decrease in the Urbach energy from 0.131 eV to 0.074 eV. These findings indicate that Mn substitution successfully improves the crystallinity quality and modifies the electronic properties of Fe3O4, thus potentially being applied in the fields of photocatalysis and optoelectronics.
Keywords: SPION- Manganese Doping- Iron Sand- Energy Gap- Crystal Structure
