New Insights into the Magnetic Properties of CoFe<sub>2</sub>O<sub>4</sub>@SiO<sub>2</sub>@Au Magnetoplasmonic Nanoparticles
Rareș Bortnic,
Adam Szatmari,
Gabriela Souca,
Răzvan Hirian,
Roxana Dudric,
Lucian Barbu-Tudoran,
Valentin Toma,
Rareș Știufiuc,
Romulus Tetean,
Emil Burzo
Affiliations
Rareș Bortnic
Faculty of Physics, “Babes Bolyai” University, 400084 Cluj-Napoca, Romania
Adam Szatmari
Faculty of Physics, “Babes Bolyai” University, 400084 Cluj-Napoca, Romania
Gabriela Souca
Faculty of Physics, “Babes Bolyai” University, 400084 Cluj-Napoca, Romania
Răzvan Hirian
Faculty of Physics, “Babes Bolyai” University, 400084 Cluj-Napoca, Romania
Roxana Dudric
Faculty of Physics, “Babes Bolyai” University, 400084 Cluj-Napoca, Romania
Lucian Barbu-Tudoran
Electron Microscopy Center “Prof. C. Crăciun”, Faculty of Biology & Geology, “Babes-Bolyai” University, 400006 Cluj-Napoca, Romania
Valentin Toma
Department of Bionanoscopy, MedFuture Research Center for Advance Medicine, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400337 Cluj-Napoca, Romania
Rareș Știufiuc
Department of Bionanoscopy, MedFuture Research Center for Advance Medicine, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400337 Cluj-Napoca, Romania
Romulus Tetean
Faculty of Physics, “Babes Bolyai” University, 400084 Cluj-Napoca, Romania
Emil Burzo
Faculty of Physics, “Babes Bolyai” University, 400084 Cluj-Napoca, Romania
We report the successful synthesis and a complete magnetic characterization of CoFe2O4@SiO2@Au magnetoplasmonic nanoparticles. The CoFe2O4 magnetic nanoparticles were prepared using the hydrothermal method. A subsequent SiO2 shell followed by a plasmonic Au shell were deposited on the magnetic core creating magnetoplasmonic nanoparticles with a core–shell architecture. A spin-glass-type magnetism was shown at the surface of the CoFe2O4 nanograins. Depending on the external magnetic field, two types of spin-glass were identified and analyzed in correlation with the exchange field acting on octahedral and tetrahedral iron sites. The magnetization per formula unit of the CoFe2O4 core is not changed in the case of CoFe2O4@SiO2@Au nanocomposites. The gold nanoparticles creating the plasmonic shell show a giant diamagnetic susceptibility, dependent on their crystallite sizes.