Abstract

The epoxy/magnetite nanocomposites express superparamagnetism under a static or low-frequency electromagnetic field. At the microwave frequency, said the X-band, the nanocomposites reveal an unexpected diamagnetism. To explain the intriguing phenomenon, we revisit the Debye relaxation law with the memory effect. The magnetization vector of the magnetite is unable to synchronize with the rapidly changing magnetic field, and it contributes to diamagnetism, a negative magnetic susceptibility for nanoparticles. The model just developed and the fitting result can not only be used to explain the experimental data in the X-band but also can be used to estimate the transition frequency between paramagnetism and diamagnetism.

Details

Title
Frequency-induced negative magnetic susceptibility in epoxy/magnetite nanocomposites
Author
Che-Hao, Chang 1 ; Su Shih-Chieh 2 ; Chang Tsun-Hsu 3 ; Ching-Ray, Chang 4 

 National Tsing Hua University, Interdisciplinary Program of Sciences, Hsinchu, Taiwan (GRID:grid.38348.34) (ISNI:0000 0004 0532 0580) 
 National Tsing Hua University, Department of Physics, Hsinchu, Taiwan (GRID:grid.38348.34) (ISNI:0000 0004 0532 0580) 
 National Tsing Hua University, Interdisciplinary Program of Sciences, Hsinchu, Taiwan (GRID:grid.38348.34) (ISNI:0000 0004 0532 0580); National Tsing Hua University, Department of Physics, Hsinchu, Taiwan (GRID:grid.38348.34) (ISNI:0000 0004 0532 0580) 
 National Taiwan University, Department of Physics, Taipei, Taiwan (GRID:grid.19188.39) (ISNI:0000 0004 0546 0241) 
Publication year
2021
Publication date
2021
Publisher
Nature Publishing Group
e-ISSN
20452322
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2487165158
Copyright
© The Author(s) 2021. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.