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Full-Text Articles in Electromagnetics and Photonics
Large Tunability Of Néel Temperature By Growth-Rate-Induced Cation Inversion In Mn-Ferrite Nanoparticles, Aria Yang, C. Chinnasamy, J. Greneche, Yajie Chen, Soack Yoon, Kailin Hsu, C. Vittoria, V. Harris
Large Tunability Of Néel Temperature By Growth-Rate-Induced Cation Inversion In Mn-Ferrite Nanoparticles, Aria Yang, C. Chinnasamy, J. Greneche, Yajie Chen, Soack Yoon, Kailin Hsu, C. Vittoria, V. Harris
Vincent G. Harris
The tuning of Néel temperature by greater than 100 K in nanoparticle Mn-ferrite was demonstrated by a growth-rate-induced cation inversion. Mn-ferrite nanoparticles, having diameters from 4 to 50 nm, were synthesized via coprecipitation synthesis. The Neel temperature (TN) increased inversely to the cation inversion parameter,δ (i.e., defined as (Mn1-δFeδ)tet[MnδFe2-δ]octO₄). Concomitantly, TN increased with increased particle growth rate and particle size. These results unambiguously establish cation inversion as the dominant mechanism in modifying the superexchange leading to enhanced TN. The ability to tailor TN enables greater flexibility in applying nanoparticle ferrites in emerging technologies.
Size Dependent Magnetic Properties And Cation Inversion In Chemically Synthesized Mnfe₂O₄ Nanoparticles, C. N. Chinnasamy, Aria Yang, S. D. Yoon, Kailin Hsu, M. D. Shultz, E. E. Carpenter, S. Mukerjee, C. Vittoria, V. G. Harris
Size Dependent Magnetic Properties And Cation Inversion In Chemically Synthesized Mnfe₂O₄ Nanoparticles, C. N. Chinnasamy, Aria Yang, S. D. Yoon, Kailin Hsu, M. D. Shultz, E. E. Carpenter, S. Mukerjee, C. Vittoria, V. G. Harris
Vincent G. Harris
MnFe₂O₄ nanoparticles with diameters ranging from about 4 to 50 nm were synthesized using a modified coprecipitation method. X-ray diffractograms revealed a pure phase spinel ferrite structure for all samples. Transmission electron microscopy showed that the particles consist of a mixture of both spherical (smaller) and cubic (larger) particles dictated by the reaction kinetics. The Néel temperatures (TN) of MnFe₂O₄ for various particle sizes were determined by using high temperature magnetometry. The ∽4 nm MnFe₂O₄ particles showed a TN of about 320°C whereas the ∽50 nm particles had a TN of about 400°C. The high Neel temperature, compared with the …