Dataset for Novel Scalable Mesoporous Silica-Assisted Synthesis of High-Quality ε-Fe2O3 Nanoparticles Revealing Extraordinarily High Coercivity

This repository contains data from the manuscript: Medříková, Z., Víchová, V., Kašlík, J., Medřík, I., & Malina, O. (2025). Novel scalable mesoporous silica-assisted synthesis of high-quality ε-Fe2O3 nanoparticles revealing extraordinarily high coercivity. Materials Today Chemistry, 67, 102809. https://doi.org/10.1016/j.mtchem.2025.102809 Abstract of the manuscript: A new, scalable synthesis of ε-Fe2O3, an intermediate polymorph of iron oxide exhibiting a giant coercive field (HC) was proposed. This study focuses on the preparation of ε-Fe2O3 through the co-precipitation of magnetite nanoparticles, their simultaneous coating with mesoporous silica, and air-annealing at sintering temperatures ranging from 1050 to 1125 °C. Structural and magnetic measurements were conducted to identify the optimal conditions for critical parameters of the synthesis, including silica content, annealing temperature and time. These conditions resulted in the production of nearly single-phase ε-Fe2O3 (over 95%) with an exceptionally large coercivity of 22 kOe without any additional metal doping. This achievement is attributed to the mesoporous silica coating, which altered the parameters of the heat-induced phase transformation pathway when compared with the silica-coated precursor. The mesoporous silica coating resulted in improving the ε-Fe2O3 stability during thermal treatment while the silica coating of magnetite particles achieved only 75% purity at the same conditions.