Effenberger, Fernando B.
Carbonari, A. W.
Rossi, L. M.
Total Authors: 3
 Ctr Univ FEI, Av Humberto de Alencar Castelo Branco 3972, BR-09850901 Sao Bernardo Do Campo - Brazil
 Univ Sao Paulo, Inst Pesquisas Energet & Nucl, BR-05508000 Sao Paulo, SP - Brazil
 Univ Sao Paulo, Inst Quim, Av Prof Lineu Prestes 748, BR-05508000 Sao Paulo - Brazil
Total Affiliations: 3
Journal of Magnetism and Magnetic Materials;
NOV 1 2016.
Web of Science Citations:
Magnetic nanoparticles of magnetite have been synthesized by thermal decomposition and investigated by measuring the magnetic hyperfine field. Preformed Fe3O4 nanoparticles were used as seeds to produce a series of magnetic nanoparticles, with different sizes and shapes. Samples were characterized by X-ray diffraction, transmission electron microscopy, and magnetization measurements. The perturbed angular correlation (PAC) technique was used to study the influence of 1,2-octanediol on the seeding growth of the Fe3O4 by measuring hyperfine interactions. The nuclear probes (111)ln -> Cd-111 were introduced into the samples through the synthesis of first core of Fe3O4, remained in the samples after the consecutive growth. The PAC results show the presence of two probe site fractions, one characterized by a well-defined magnetic dipole frequency with population f(1) and another characterized with a broad distributed electric quadrupole frequency with population f(O), which were, respectively, assigned to probes at substitutional Fe sites in crystalline Fe3O4 formed at inner region of the nanoparticles and probes at non-crystalline iron oxide in the outer region of nanoparticles. A mathematical model was proposed to fit the behavior of f(O) with the particle size. (C) 2016 Elsevier B.V. All rights reserved. (AU)