https://www.jurnalkonstan.ac.id/index.php/jurnal <pre id="tw-target-text" class="tw-data-text tw-text-large XcVN5d tw-ta" dir="ltr" style="text-align: left;" data-placeholder="Translation"><span style="font-family: 'Noto Sans', Arial, Helvetica, sans-serif;">KONSTAN (Jurnal Fisika dan Pendidikan Fisika) is a UIN Mataram scientific journal for scientific communication in the field of Physics and Physics Education from the result of the study. This journal is published twice a year, in June and December.</span></pre> <div class="page"> <p>KONSTAN (Jurnal Fisika dan Pendidikan Fisika)<span class="tlid-translation translation"><span title="">has been accredited</span></span>&nbsp;by the Ministry of Research, Technology, and Higher Education of the Republic of Indonesia, Decree&nbsp;No. 177/E/KPT/2024, with&nbsp;<strong>SINTA 4</strong></p> <p>KONSTAN (Jurnal Fisika dan Pendidikan Fisika) is a scientific journal that publishes articles from physics and physics education.&nbsp; Various topics of physics and physics education articles that can be accepted in this journal are:</p> <ul> <li class="show"> <p>Physics Education Research</p> </li> <li class="show"> <p>Media Development and Learning Model of Physics</p> </li> <li class="show"> <p>Evaluation and Assessment of Learning Physics</p> </li> <li class="show"> <p>Research and Development of Physics Education</p> </li> <li class="show"> <p>Physics theory</p> </li> <li class="show"> <p>Applied Physics</p> </li> </ul> </div> Universitas Islam Negeri (UIN) Mataram en-US KONSTAN - JURNAL FISIKA DAN PENDIDIKAN FISIKA 2460-9110 https://www.jurnalkonstan.ac.id/index.php/jurnal/article/view/786 <p>Doping is a practical approach to altering a material's electronic and structural properties, thereby influencing its optical and magnetic characteristics. This study successfully synthesized and characterized cobalt-doped magnetite (Fe2.5Co0.5O4) nanoparticles from natural iron sand via coprecipitation. The main objective was to evaluate the optical properties of the synthesized material using UV-Vis spectroscopy and to compare band gap energies using three approaches: the Tauc method (direct and indirect transitions), the Kubelka–Munk method, and the Urbach energy, an indicator of structural disorder. The characterization results revealed that the incorporation of Co2+ ions into the magnetite structure induced significant changes in the absorption spectra, including the emergence of new peaks and a redshift in the wavelength. The obtained band gap values were 3.71 eV (Tauc-direct), 2.18 eV (Tauc-indirect), and 2.33 eV (Kubelka–Munk), confirming the presence of two types of optical transitions. Furthermore, the relatively low Urbach energy (0.07138 eV) indicated that the crystal structure remained well-preserved despite the modifications induced by doping. This study highlights the importance of employing multi-method approaches for reliable optical characterization and demonstrates that Fe2.5Co0.5O4 materials derived from local resources show promise for photocatalytic and optoelectronic applications.</p> Kormil Saputra Rahmatun Inayah Ika Umratul Asni Aminy Teguh Ardianto Dian Wijaya Kurniawidi ##submission.copyrightStatement## 2025-12-24 2025-12-24 10 02 1 11 10.20414/konstan.v10i02.786