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Waldemar A. A. Macedo
Researcher at National Nuclear Energy Commission
Publications - 112
Citations - 3619
Waldemar A. A. Macedo is an academic researcher from National Nuclear Energy Commission. The author has contributed to research in topics: Coercivity & Nanoparticle. The author has an hindex of 29, co-authored 108 publications receiving 3125 citations. Previous affiliations of Waldemar A. A. Macedo include Catalan Institution for Research and Advanced Studies & University of California, San Diego.
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Journal ArticleDOI
Cubic versus spherical magnetic nanoparticles: the role of surface anisotropy.
German Salazar-Alvarez,Jian Qin,Vladimir Šepelák,I. Bergmann,M. Vasilakaki,Kalliopi N. Trohidou,José D. Ardisson,Waldemar A. A. Macedo,Maria Mikhaylova,Mamoun Muhammed,Maria Dolors Baró,Josep Nogués +11 more
TL;DR: The experimental effective anisotropy and the Monte Carlo simulations indicate that the different random surface an isotropy of the two morphologies combined with the low magnetocrystalline anisOTropy of gamma-Fe2O3 is the origin of these effects.
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Nanosized powders of NiZn ferrite: Synthesis, structure, and magnetism
Adriana Silva de Albuquerque,José D. Ardisson,Waldemar A. A. Macedo,Maria do Carmo Martins Alves +3 more
TL;DR: In this paper, the structure and magnetic behavior of nanostructured powders of stoichiometric NiZn ferrite, Ni0.5Zn 0.5Fe2O4, synthesized by coprecipitation, are investigated by extended x-ray-absorption fine structure spectroscopy (EXAFS), xray diffraction, and vibrating sample magnetometry.
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Significant Dzyaloshinskii-Moriya interaction at graphene-ferromagnet interfaces due to the Rashba effect.
Hongxin Yang,Hongxin Yang,Hongxin Yang,Gong Chen,Gong Chen,Alexandre A. C. Cotta,Alpha T. N'Diaye,Sergey A. Nikolaev,Edmar A. Soares,Waldemar A. A. Macedo,Kai Liu,Andreas K. Schmid,Albert Fert,Mairbek Chshiev +13 more
TL;DR: It is demonstrated that chiral spin textures are induced at graphene/ferromagnetic metal interfaces, and this work paves a path towards two-dimensional-material-based spin–orbitronics.
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Magnetism of Epitaxial fcc-Fe(100) Films on Cu(100) Investigated in Situ by Conversion-Electron Mössbauer Spectroscopy in Ultrahigh Vacuum
TL;DR: In this article, it was shown that fcc Fe(100) stabilized at a lattice constant close to that of Cu has an antiferromagnetic ground state, and showed that it is magnetically ordered and shows a small average hyperfine field, e.g., 1.1 T at 29 K for 10 monolayers.
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Cr-containing magnetites Fe3-xCrxO4: The role of Cr3+ and Fe2+ on the stability and reactivity towards H2O2 reactions
Fabiano Magalhães,Márcio C. Pereira,S.E.C. Botrel,José Domingos Fabris,Waldemar A. A. Macedo,Renato de Mendonça,Rochel M. Lago,Luiz C.A. Oliveira +7 more
TL;DR: A series of Cr-containing magnetites, Fe3−xCrxO4 (x = 0.00, 0.07,0.42 and 0.51) has been prepared using conventional co-precipitation method in this paper, which showed that the presence of Cr has a remarkable effect on the texturial properties of the material decreasing the pore diameter from meso-to micropore with a significant increase on the BET surface area.