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Porous Fe 3 O 4 Nanospheres with Controlled Porosity for Enhanced Electromagnetic Wave Absorption
Author(s) -
Kuchi Rambabu,
Dongquoc Viet,
Surabhi Srivathsava,
Kim Dojin,
Yoon SoonGil,
Park SeungYoung,
Choi Jihoon,
Jeong JongRyul
Publication year - 2018
Publication title -
physica status solidi (a)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.532
H-Index - 104
eISSN - 1862-6319
pISSN - 1862-6300
DOI - 10.1002/pssa.201701032
Subject(s) - porosity , materials science , reflection loss , ostwald ripening , nanocrystal , chemical engineering , absorption (acoustics) , porous medium , magnetite , dielectric , nanoparticle , nanotechnology , composite material , composite number , optoelectronics , metallurgy , engineering
Porous magnetite (Fe 3 O 4 ) nanospheres are successfully prepared through a one‐pot solvothermal method with a gas‐bubble‐assisted Ostwald ripening process. The formation mechanism is explored by studying the reaction parameters, including the concentration of the precipitating agent, capping agent, and urea gas source for a fixed reaction temperature and time. The authors’ results show that the Fe 3 O 4 nanospheres are composed of many primary nanocrystals, the sizes of which are well regulated by urea concentration. As such, the size of the spherical primary nanocrystal determines the porosity of Fe 3 O 4 nanospheres. Strong reflection loss of −49.2 dB is observed at 11.9 GHz for highly porous Fe 3 O 4 nanospheres with a thickness of 2.7 mm due to multiple scatterings in void spaces and increased dielectric loss caused by higher interfacial polarization relaxation loss in the porous structure. The authors believe that the prepared porous Fe 3 O 4 nanospheres are good candidates for electromagnetic absorption applications.