Dissertation defense
Student: Murilo Zanardi Mattedi
Program: Geophysics
Title: “Debye decomposition of magnetic susceptibility spectra: an approach to estimate the magnetic grain size in the SP-SD range”
Advisor: Profa. Dra. Andréa Teixeira Ustra
Judging Committee
- Profa. Dra. Andréa Teixeira Ustra (IAG/USP - orientadora)
- Dr. Plínio Francisco Jaqueto - Observatório Nacional
- Prof. Dr. Gelvam André Hartmann - UNICAMP
Abstract
This work aims to evaluate frequency-dependent magnetic susceptibility responses to estimate the magnetic grain size in the superparamagnetic (SP) and single-domain (SD) ranges, using the Debye relaxation model, to justify the feasibility of its application. By performing the Debye decomposition, estimates of the magnetic mineral size were obtained, which allowed for the assumption of the presence or not of minerals in the superparamagnetic spectrum, which allowed for the distinction of the studied environments. The three areas investigated in this study yielded different results, as predicted and expected by the model, and confirmed that the Debye relaxation model contributes to the assessment of the grain size of ferromagnetic minerals in the SP-SD range
Keywords: environmental magnetism, magnetic susceptibility, inversion theory, Debye relaxation model.