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Frequency-induced negative magnetic susceptibility in epoxy/magnetite nanocomposites.

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.

SUBMITTER: Chang CH

PROVIDER: S-EPMC7870892 | biostudies-literature | 2021 Feb

REPOSITORIES: biostudies-literature

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Frequency-induced negative magnetic susceptibility in epoxy/magnetite nanocomposites.

Chang Che-Hao CH Su Shih-Chieh SC Chang Tsun-Hsu TH Chang Ching-Ray CR

Scientific reports 20210208 1

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 na ...[more]

PMID: 33558574

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