Magnetic Phenomena in MFe2O4 Nanoparticle Cluster Systems

• Grant number: 25/09155-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2025
• End date: July 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Diego Muraca
• Grantee: Jonatas Rodrigues de Menezes
• Host Institution: Instituto de Física Gleb Wataghin (IFGW). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

This project is a continuation of the research initiated in 2023 under a PIBIC scholarship. The main objective is to deepen the study of phenomenological models for determining the effective anisotropy constant Keff in magnetic nanoparticles (MNPs) and in clusters of MNPs. These MNPs are generally composed of Fe3O4 (magnetite) and CoxFe3-xO4 (cobalt-doped magnetite, where x denotes the proportion of Co^{2+} ions). Accurate understanding and determination of Keff are essential to properly correlate with the effects of magnetic hyperthermia, a phenomenon involving the conversion of electromagnetic energy into heat. To this end, different phenomenological models for magnetite or cobalt ferrites will be evaluated, considering variations in size and geometry, to assess under which conditions these models are validly applicable. Furthermore, such phenomenological models will be explored in systems of interacting MNPs.The various samples will undergo a comprehensive investigation of their magnetic, morphological, and calorimetric properties (magnetic hyperthermia - MH), with the aim of correlating them with phenomenological models. Structural characterizations will be carried out using X-ray Diffraction, Transmission Electron Microscopy, and Scanning Electron Microscopy\footnote{Some of these characterizations have already been performed.}. Magnetic measurements such as DC magnetization under applied field, temperature-dependent magnetization, AC susceptibility, and magnetic remanence are planned, utilizing the SQUID (Superconducting Quantum Interference Device) and PPMS (Physical Properties Measurement System) equipment available at IFGW. MH studies will be conducted at different field strengths and frequencies using equipment from the Laboratory of Metals and Alloys at IFGW.The scholarship candidate has previously worked with nanomagnetism concepts during their past PIBIC research, which earned them a scientific merit award. That is, their work was recognized among the top 20 research projects at the XXXII Unicamp Scientific Initiation Congress.