Optical Band Gap and Urbach Energy of Cobalt-Doped Magnetite Nanoparticles Derived from Loang Balok Iron Sand

2026-01-27T02:28:10+00:00

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.

Exploring Science Students’ Creativity and Critical Thinking Skills through Fluid Learning

2026-01-27T02:31:48+00:00

Amid rapid technological Development, creative thinking skills are highly sought after. Creativity enables individuals to generate new ideas, find innovative solutions in complex situations, and adapt more easily to change. This study aims to determine the level of creative thinking skills of prospective science teachers through four primary indicators: flexibility of thinking, fluency in generating ideas, originality of ideas, and the ability to elaborate ideas. This study used a quantitative descriptive approach and involved 20 prospective science teachers at Lamongan Islamic University. The research instrument was a Likert-scale questionnaire. Data were analyzed by assigning a score to each statement, followed by descriptive statistics including averages, frequency distributions, percentages, and standard deviations. Furthermore, students' abilities were categorized by score, and creative thinking skills received the highest score on the fluency indicator (81.20%), while flexibility received the lowest (53.40%). For critical thinking skills, indicators of giving building (55.55%) and organizing strategies and explanations of inference skills are in the low category (54.70%). This condition is caused by students' difficulties in generating new ideas or generating various alternative solutions when facing a problem. Therefore, the results of this study are expected to inform educators in developing learning strategies that stimulate the creativity of prospective science teachers, for example, through learning modules that train 21st-century skills, discovery-based approaches, or the use of media that encourage students to be more daring in their creations.

KONSTAN - JURNAL FISIKA DAN PENDIDIKAN FISIKA

Optical Band Gap and Urbach Energy of Cobalt-Doped Magnetite Nanoparticles Derived from Loang Balok Iron Sand

Exploring Science Students’ Creativity and Critical Thinking Skills through Fluid Learning