Size and doping effects on the improvement of the low-temperature magnetic properties of magnetically aligned cobalt ferrite nanoparticles

Autor(es)

Tancredi, Pablo ^{[1, 2]} ; Rivas-Rojas, Patricia C. ^{[3, 2]} ; Moscoso-Londono, Oscar ^[4] ; Muraca, Diego ^[5] ; Knobel, Marcelo ^[5] ; Socolovsky, Leandro M. ^[6]

Afiliação do(s) autor(es)

^[1] Natl Inst Ind Technol, Funct Nanomat INTI Micro & Nanotechnol, CP B1650, San Martin, Buenos Aires - Argentina

^[2] Univ Buenos Aires CONICET, Fac Engn, Lab Amorphous Solids INTECIN, CP C1063, Buenos Aires, DF - Argentina

^[3] Natl Univ San Martin, Sch Sci & Technol, Lab Appl Crystallog, CP B1650, San Martin, Buenos Aires - Argentina

^[4] Univ Autonoma Manizales, Antigua Estn Ferrocarril, Manizales 170001 - Colombia

^[5] Univ Campinas UNICAMP, Inst Fis Gleb Wataghin, BR-13083859 Campinas, SP - Brazil

^[6] Natl Technol Univ CIT Santa Cruz CONICET, Santa Cruz Reg Sch, CP Z9400, Rio Gallegos, Santa Cruz - Argentina

• Tipo de documento: Artigo Científico
• Fonte: Journal of Alloys and Compounds; v. 894, FEB 15 2022.
• Citações Web of Science: 0

Resumo

The macroscopic magnetic behavior of nanoparticulated systems is the result of several contributions, ranging from the intrinsic structural properties of the nanoparticles to their spatial arrangement within the material. Unravelling and understanding these influences is an important task to produce nano-systems with improved properties for specific technological applications. In this work we study how the magnetic behavior of a set of magnetically hard nanoparticles can be improved by the modification of the sample arrangement (either randomly or magnetically oriented) and the nature of the enclosing matrices. At first, we employed a hot-injection, continuous growth strategy to synthesize non-stoichiometric cobalt ferrite (CoxFe(3-x)O(4)) nanoparticles. We prepared five batches of hydrophobic, oleate-coated samples, with mean diameters of 8 nm, 12 nm, 16 nm and variable Co-to-Fe proportions. The structural characterization con-firms that the nanoparticles have a spinel-type monocrystalline structure and that the Co and Fe ions are homogenously distributed within the system. The magnetic properties of the nanoparticles were measured by DC magnetometry, and we found that the strategy used in this work to create a system of magnetically oriented nanoparticles can lead to a significant remanence and coercive field enhancement at low temperatures when compared with randomly oriented and fixed systems. The modification of the magnetic properties was detected in the five batches of samples, but the strength of the enhancement depends on both size and composition of the nanoparticles. Indeed, for the ``hardest{''} samples the coercive field of the magnetically oriented systems reached values of around 30 kOe (3 T), which represents a 50% increase regarding the randomly oriented system and are among the highest reported to date for a set of Fe and Co oxide nanoparticles. (C) 2021 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 14/26672-8 - Efeitos de interface e superfície em nanoheteroestruturas magnético-metálicas
• Beneficiário: Oscar Moscoso Londono
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado